P5 Ai Flashcards
What is a vector quantity?
A vector quantity has a magnitude (size) and a direction.
Examples of vector quantities include force, velocity, displacement, and acceleration.
What are scalar quantities?
Scalar quantities have a magnitude but no direction.
Examples of scalar quantities include speed, distance, mass, temperature, and time.
How are vectors usually represented?
Vectors are usually represented by an arrow.
The length of the arrow shows the magnitude, and the direction of the arrow shows the direction of the quantity.
What is a force?
A force is a push or a pull that acts on an object.
What causes forces to act?
Forces are caused by objects interacting with each other.
What are contact forces?
Contact forces are forces that require two objects to be touching.
Examples include friction, air resistance, tension, and normal contact force.
What are non-contact forces?
Non-contact forces are forces that do not require objects to be touching.
Examples include magnetic force, gravitational force, and electrostatic force.
What happens when an object exerts a force on another object?
The second object pushes back, which is the normal contact force.
What is an interaction pair?
An interaction pair consists of two forces that are equal in size but act in opposite directions.
Give an example of an interaction pair.
The gravitational attraction between the Earth and the Sun.
Fill in the blank: A force is a _____ or a _____ that acts on an object.
[push] [pull]
True or False: All forces are either contact or non-contact forces.
True
Name one contact force and one non-contact force that act on a dropped tennis ball.
Contact force: [friction]
Non-contact force: [gravitational force]
What is mass measured in?
Kilograms (kg)
Mass is the amount of matter in an object.
What is the definition of mass?
The amount of matter (stuff) in an object
Mass is constant regardless of location.
What is the term for the point where the weight of an object can be considered to act from?
Centre of mass
This point is crucial for understanding how weight is distributed.
What is weight measured in?
Newtons (N)
Weight is the force acting on an object due to gravity.
How is weight defined?
The force acting on an object due to gravity
This force acts from an object’s centre of mass.
What causes the weight of an object near Earth?
The gravitational field around the Earth
The strength of the gravitational field can vary based on location.
How does the weight of an object change?
It depends on the object’s location
Unlike mass, which remains constant.
How can weight be measured?
Using a calibrated spring balance (newtonmeter)
This instrument allows for accurate measurement of weight.
What is the relationship between mass and weight?
They are directly proportional
This means as one increases, the other does as well.
What is the formula to calculate weight?
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
For Earth, gravitational field strength is approximately 9.8 N/kg.
What is the gravitational field strength on Earth?
Approximately 9.8 N/kg
This value is used in weight calculations on Earth.
If a motorcycle weighs 2401 N on Earth, what is its mass?
245 kg
Calculation: mass = weight ÷ gravitational field strength = 2401 ÷ 9.8.
Calculate the weight in newtons of a 5 kg mass on Earth.
49 N
Calculation: Weight = 5 kg x 9.8 N/kg.
Calculate the weight in newtons of a 5 kg mass on the Moon (g = 1.6 N/kg).
8 N
Calculation: Weight = 5 kg x 1.6 N/kg.
True or False: Weight is a measure of how much matter is in an object.
False
Weight is a force due to gravity, while mass measures matter.
Fill in the blank: Weight is a force due to _______.
Gravity
Weight changes with gravitational strength.
What is a Resultant Force?
The overall force on a point or object
A Resultant Force can replace multiple forces acting at a single point with a single force that has the same effect as the original forces.
How do you calculate the Resultant Force when forces are acting in a straight line?
Add together forces acting in the same direction and subtract those going in the opposite direction
Example: If one force is 5 N to the left and another is 10 N to the right, the resultant force is 5 N to the right.
What happens when a force moves an object?
Work is done and energy is transferred to the object
‘Work done’ and ‘energy transferred’ are considered the same thing.
What is the relationship between work done and frictional forces?
Work is often done against frictional forces, causing energy to be transferred to the thermal energy store of the object
This results in an increase in temperature of the object.
What is the formula for calculating work done?
W = Fs
Where W is work done, F is force, and s is distance moved along the line of action of the force.
What is one joule of work defined as?
One joule of work is done when a force of one newton causes an object to move a distance of one meter in the direction of the force
This establishes the relationship between joules and newton meters.
Fill in the blank: Work done is equal to _______.
Force x Distance
This is represented by the formula W = Fs.
True or False: When you push an object along a rough surface, some energy is transferred to the kinetic energy store of the object.
True
This occurs because the object starts moving.
What happens to the temperature of an object when work is done against friction?
The temperature of the object increases
This is due to energy being transferred to the thermal energy store.
What does the line of action of the force refer to?
The direction of the force
This is important for calculating work done.
If a force of 20 N pushes an object 20 cm, how do you calculate the work done on the object?
Convert 20 cm to meters and use W = Fs
Work done would be calculated as W = 20 N * 0.2 m = 4 J.
What happens when more than one force acts on an object?
It can stretch, compress, or bend, transferring energy.
What is elastic deformation?
An object can return to its original shape and length after the force is removed.
What happens if an object does not return to its original shape after a force is removed?
It has been inelastically deformed.
What are elastic objects?
Objects that can be plastically deformed, e.g., springs.
What is done when a force stretches or compresses an object?
Work is done.
What does work done on a spring transfer to?
The elastic potential energy store of the object.
What is the relationship between extension and force for a spring?
Extension is directly proportional to force up to a given limit.
What is the formula for the force exerted by a spring?
F = ke, where F is force, k is the spring constant, and e is extension.
What does the spring constant depend on?
The object that is being stretched.
What is the natural length of a spring?
The length of the unstretched spring.
What happens to the relationship between force and extension when the spring is stretched past its limit of proportionality?
The relationship becomes non-linear.
What indicates the limit of proportionality on a graph of force versus extension?
Point P, where the line starts to bend.
True or False: The equation F = ke holds true past the limit of proportionality.
False.
Fill in the blank: The gradient of the straight line on a force vs extension graph is equal to _______.
the spring constant k.
What happens when you apply a force of 1 N to a fixed spring that extends by 2 cm?
You can calculate the spring constant.
What is the first step in investigating the link between force and extension in springs?
Measure the mass of each mass
This is the initial step before applying any force to the spring.
How do you calculate the weight (force applied) when investigating springs?
W = mg
Where W is weight, m is mass, and g is the acceleration due to gravity (approximately 9.81 m/s²).
What should you do after measuring the original (natural) length of the spring?
Add a mass to the spring and allow it to come to rest
This step is crucial to obtain the new length of the spring under load.
What is the formula to find the extension of the spring?
Extension = new length - original length
This formula helps quantify how much the spring has stretched.
What is the minimum number of measurements required before reaching the limit of proportionality?
At least 5 measurements
This ensures accurate data for plotting a force-extension graph.
What is the formula to calculate the energy stored in a spring’s elastic potential energy store?
E = ½ke²
Where E is the elastic potential energy, k is the spring constant, and e is the extension.
If a spring has a spring constant of 500 N/m and extends elastically by 10 cm, how much energy is stored?
2.5 J
The calculation involves converting 10 cm to meters and applying the energy formula.
Fill in the blank: The work done in stretching a spring can be found using the formula E = _______.
½ke²
How is energy transferred to the spring as it is deformed?
It is stored in the spring’s elastic potential energy store
This energy is released when the spring returns to its original shape.
True or False: A spring can store energy when it is compressed.
True
The energy stored can be calculated using the same formula for elastic potential energy.
What is the spring constant if a spring extends elastically by 2.5 cm?
40 N/m
This value is used in the energy calculation for the elastic potential energy.
What is distance?
Distance is just how far an object has moved
Distance is a scalar quantity, which means it does not involve direction.
What is the difference between distance and displacement?
Distance is scalar; displacement is vector
Displacement measures the distance and direction in a straight line from an object’s starting point to its finishing point.
What does displacement measure?
Displacement measures distance and direction in a straight line
It is determined from an object’s starting point to its finishing point.
Speed is a _______ quantity.
scalar
Velocity is a _______ quantity.
vector
How is speed defined?
Speed is just how fast you’re going (e.g. 30 mph)
It does not include direction.
How is velocity defined?
Velocity is speed in a given direction (e.g. 30 mph north)
It combines both speed and direction.
What is the formula to calculate speed?
s = vt
Where s is distance travelled (m), v is speed (m/s), and t is time (s).
True or False: Objects rarely travel at a constant speed.
True
What factors can affect a person’s speed while walking, running, or cycling?
- Their fitness
- The distance they’ve travelled
- Their age
- The terrain
What are some typical speeds of objects? List at least three.
- A person walking - 1.5 m/s
- A person running - 3 m/s
- A car - 25 m/s
What is a typical speed for sound in air?
330 m/s
Fill in the blank: The speed of a sprinter who runs 200 m in 25 s is _______.
8 m/s
What is acceleration?
The change in velocity in a certain amount of time.
How can you find the average acceleration of an object?
Acceleration (m/s²) = Change in velocity (m/s) ÷ Time taken (s)
What is deceleration?
Negative acceleration when something slows down.
What is uniform acceleration?
Constant acceleration.
What is the approximate value of acceleration due to gravity (g) near the Earth’s surface?
Roughly equal to 9.8 m/s².
Fill in the blank: Acceleration due to gravity is uniform for objects ________.
falling freely.
What equation can be used for uniform acceleration?
v² = u² + 2as
In the equation v² = u² + 2as, what does ‘u’ represent?
Initial velocity (m/s)
If a van is traveling at 23 m/s and decelerating at 2.0 m/s² over a distance of 112 m, what will its speed be when it reaches the built-up area?
9 m/s
What is the typical speed of a bicycle?
About 6 m/s.
How do you estimate acceleration?
Use typical speeds and time taken.
True or False: An estimate is just a guess using rough numbers for things.
True
What does the symbol ‘~’ signify in an acceleration estimate?
It’s an approximate answer.
If a ball is dropped from a height and hits the ground at 7 m/s, how do you calculate the height it was dropped from?
Use the equation h = (v²) ÷ (2g), where g is acceleration due to gravity.
What is the significance of the negative sign in acceleration when decelerating?
It indicates a reduction in speed.
List the steps to estimate the acceleration of an object.
- Identify typical speed
- Determine time taken
- Use the acceleration formula
What is acceleration?
The change in velocity in a certain amount of time.
How do you calculate average acceleration?
a = Change in velocity (m/s) ÷ Time taken (s)
What is deceleration?
Negative acceleration when something slows down.
What is uniform acceleration?
Constant acceleration.
What is the approximate value of acceleration due to gravity (g) near the Earth’s surface?
9.8 m/s²
What is the equation for uniform acceleration?
v² = u² + 2as
What does ‘u’ represent in the uniform acceleration equation?
Initial velocity (m/s)
Estimate the acceleration of a bicycle that reaches a speed of 6 m/s in 10 seconds.
~0.6 m/s²
What is the typical speed of a bike?
About 6 m/s
If a van is travelling at 23 m/s and decelerates at 2.0 m/s² over 112 m, what will its speed be when it reaches the built-up area?
9 m/s
True or False: The initial velocity is the speed of the object when it starts moving.
True
Fill in the blank: Acceleration is how quickly you’re _______.
speeding up
What is an estimate?
A guess using rough numbers for things.
What does the symbol ‘~’ represent in calculations?
It indicates an approximate answer.
What should you do if you are not told what equation to use in an exam for uniform acceleration?
Make a list of the information you’re given to help you see what to do.
Calculate the height a ball is dropped from if it hits the ground at 7 m/s and acceleration due to gravity is ~9.8 m/s².
[Calculation required]
What is the purpose of distance-time graphs?
To show journeys and understand motion
What does a flat section on a distance-time graph indicate?
The object is stationary
What does a straight uphill section on a distance-time graph represent?
The object is traveling at a steady speed
What do curves on a distance-time graph signify?
Acceleration or deceleration
What does a curve that is getting steeper mean?
The object is speeding up (accelerating)
What does a leveling off curve indicate?
The object is slowing down (decelerating)
How is speed calculated from a distance-time graph?
Gradient = change in vertical axis / change in horizontal axis
What is the first step in calculating speed from the graph?
Find the gradient of the graph
How do you find the change in time for speed calculation?
Use the horizontal side of a triangle drawn on the graph
How do you find the change in distance for speed calculation?
Use the vertical side of a triangle drawn on the graph
Calculate the speed if the change in distance is 9 m and the change in time is 3.6 s.
Speed = 2.5 m/s
What does a steeper gradient on a distance-time graph represent?
A faster speed
Fill in the blank: The gradient of a distance-time graph is equal to _______.
[speed]
True or False: A distance-time graph can only show motion in one direction.
False
What should you be able to do with distance-time graphs?
Draw, understand, and describe journeys
Sketch a distance-time graph for an object that accelerates, travels at a steady speed, and then comes to a stop.
Graph should show initial curve (acceleration), straight line (steady speed), and leveling off (stop)
What does a velocity-time graph represent?
It shows how an object’s velocity changes over time.
In a velocity-time graph, what does a flat section indicate?
Travelling at a steady speed.
What does a steeper graph indicate in a velocity-time graph?
Greater acceleration or deceleration.
What do uphill sections in a velocity-time graph represent?
Acceleration.
What do downhill sections in a velocity-time graph represent?
Deceleration.
What does a curve in a velocity-time graph indicate?
Changing acceleration.
What is drag?
The resistance experienced by an object moving through a fluid.
What is air resistance?
A type of drag experienced by objects moving through air.
How does drag behave in relation to the movement of an object?
It acts in the opposite direction to the movement.
How does drag change with the speed of an object?
Drag increases as the speed of the object increases.
What happens to an object when it first starts falling?
The force of gravity is much larger than the drag, causing acceleration.
What occurs as the speed of a falling object increases?
The drag also increases.
What is terminal velocity?
The constant speed at which the drag force equals the gravitational force.
What is the resultant force on an object at terminal velocity?
Zero.
Fill in the blank: Friction is ______ to slow things down.
always there.
What is the acceleration of a stationary car that starts accelerating for 10 seconds?
It accelerates until it reaches a speed of 20 m/s.
How long does the car travel at 20 m/s before braking?
20 seconds.
What happens during the braking phase of the car?
It decelerates uniformly and comes to a stop in 4 seconds.
True or False: An object falling under the influence of gravity will eventually reach a constant speed.
True.
What is Newton’s First Law?
A resultant force is needed to change the motion of an object
If the resultant force on a stationary object is zero, it remains stationary. If the resultant force on a moving object is zero, it continues moving at the same velocity.
What happens if the resultant force on a moving object is zero?
The object will continue moving at the same velocity
This means it will maintain the same speed and direction.
When will the velocity of an object change?
When there is a non-zero resultant force acting on it
A non-zero resultant force will cause acceleration or deceleration in the direction of the force.
What does Newton’s Second Law state about force and acceleration?
The force acting on an object and the acceleration of the object are directly proportional
This means that a larger resultant force results in greater acceleration.
How is acceleration related to mass according to Newton’s Second Law?
Acceleration is inversely proportional to the mass of the object
This means that an object with a larger mass will accelerate less than one with a smaller mass for a given force.
What is the formula that describes Newton’s Second Law?
F = ma
Where F is the resultant force in Newtons, m is mass in kilograms, and a is acceleration in m/s².
What is the mass of a typical car?
1000 kg
This is a typical value used for calculations involving cars.
What is the mass of a loaded lorry?
30,000 kg
This mass is used to estimate forces in larger vehicles.
Estimate the resultant force on an average car accelerating from rest to a speed of 25 m/s in 10 seconds.
2500 N
This is calculated using F = ma where m is 1000 kg and a is 2.5 m/s².
Fill in the blank: A non-zero resultant force will always produce ______ in the direction of the force.
acceleration
This includes both acceleration and deceleration.
True or False: An object will only accelerate if there is a resultant force acting on it.
True
This is a fundamental principle of Newton’s First Law.
What is the typical speed of a car used in the calculations?
25 m/s
This value is used for estimating acceleration and resultant force.
To find acceleration, use the formula a = ______.
Δv / t
Where Δv is the change in velocity and t is the time taken.
What does Newton’s Third Law state?
When two objects interact, the forces they exert on each other are equal and opposite.
If you push an object, what will it do?
It will push back against you, just as hard.
What happens when you stop pushing an object?
The object stops pushing back.
True or False: The forces in Newton’s Third Law act on the same object.
False
What is the relationship between mass and acceleration in Newton’s Second Law?
a = F : m.
In the example of Skater A and Skater B, who accelerates more?
Skater A, because she has a smaller mass.
What forces act on a book sitting on a table in equilibrium?
The weight of the book pulls it down and the normal contact force from the table pushes it up.
Why is the scenario of a book on a table not an example of Newton’s Third Law?
The forces are different types and both act on the book.
What are the pairs of forces due to Newton’s Third Law in the case of a book on a table?
- The book being pulled down by gravity (We) and the Earth being pulled up by the book (We) * The normal contact force from the table pushing up on the book (R) and the normal contact force from the book pushing down on the table (R)
Fill in the blank: Newton’s Third Law involves _______ and _______ forces.
equal and opposite
What must be done to understand Newton’s Third Law thoroughly?
Take your time, look at each object one by one, and work out all the forces acting on it.
What is an example of a situation demonstrating Newton’s Third Law with a car in equilibrium?
The car’s weight acting down and the normal force from the road acting up.
What is the formula for Newton’s Second Law?
F = ma
In the experiment, what is the mass, m, that you’ll be accelerating?
Total mass of the trolley, hook, and added masses
How can the mass, m, be measured in the experiment?
Using a mass balance
What does the force, F, represent in this experiment?
The weight of the hook and the masses on the hook
How is the force, F, calculated?
F = m * g (where W = mg)
What is the method to find the acceleration, a?
Record the acceleration as the trolley passes through the light gate
What must be kept constant to investigate how mass affects acceleration?
The force, F
What happens to acceleration as mass increases, according to Newton’s Second Law?
Acceleration decreases
What relationship does Newton’s Second Law describe between mass and acceleration?
Mass and acceleration are inversely proportional
What must be changed to investigate how force affects acceleration?
The force, F
What happens to acceleration as force increases, according to Newton’s Second Law?
Acceleration increases
What relationship does Newton’s Second Law describe between force and acceleration?
Force and acceleration are directly proportional
Fill in the blank: The ____ is the weight of the hook and any masses on the hook.
force
True or False: To keep the total mass the same while changing force, you can move masses from the trolley to the hook.
True
In the experiment, what is the purpose of marking a starting line on the table?
To ensure the trolley travels the same distance to the light gate
What should be recorded for each total mass, m, when investigating mass’s effect on acceleration?
The acceleration, a
What equipment is connected to the light gate in the experiment?
Data logger or computer
What is the formula for Stopping Distance?
Stopping Distance = Thinking Distance + Braking Distance
This formula is essential for understanding how different components contribute to the total distance required to stop a vehicle.
What is Thinking Distance?
The distance traveled during the driver’s reaction time
Thinking Distance is influenced by how quickly a driver reacts to a hazard.
What is Braking Distance?
The distance taken to stop under the braking force
Braking Distance starts once the brakes are applied.
How does vehicle weight affect Stopping Distance?
Heavier vehicles have a longer stopping distance
This is due to the increased inertia that heavier vehicles possess.
What are the typical stopping distances for cars at 30 mph, 60 mph, and 70 mph?
- 23 m at 30 mph
- 73 m at 60 mph
- 96 m at 70 mph
These distances provide a guideline for drivers to understand stopping distances at different speeds.
True or False: The longer it takes to perform an emergency stop, the lower the risk of crashing.
False
A longer stopping distance increases the risk of crashing into obstacles.
What factors affect Thinking Distance?
- Speed
- Reaction Time
- Tiredness
- Drugs or Alcohol
- Distractions
Each of these factors can significantly impact a driver’s ability to react quickly to hazards.
Fill in the blank: Thinking Distance increases with _______.
[increased speed]
Higher speeds result in greater distances traveled during the driver’s reaction time.
What is the impact of driving while tired on Stopping Distance?
It increases reaction time, thus increasing Thinking Distance
This longer Thinking Distance translates to a longer total Stopping Distance, increasing crash risk.
How does driving above the speed limit affect Stopping Distance?
It increases both Thinking Distance and Stopping Distance
Higher speeds mean more distance is covered during the reaction time.
What happens during an emergency stop?
Maximum force is applied by the brakes
This is done to minimize the stopping distance.
What is braking distance?
The distance a vehicle travels while coming to a stop.
What factors affect braking distance?
Braking distance is affected by:
* Speed
* Weather or road surface
* Condition of the tyres
* Condition of the brakes
How does speed impact braking distance?
The faster a vehicle travels, the longer it takes to stop for a given braking force.
What effect do weather or road surfaces have on braking distance?
Water, ice, oil, or leaves on the road reduce grip, increasing the braking distance.
What happens to a vehicle’s braking distance in wet conditions?
Wet conditions increase the chance of skidding, leading to longer braking distances.
How does the condition of tyres affect braking distance?
Bald tyres cannot effectively remove water in wet conditions, leading to skidding.
What role do brakes play in stopping a vehicle?
Brakes rely on friction between the brake pads and wheels to stop the vehicle.
What happens to energy when brakes are applied?
Energy is transferred from the vehicle’s kinetic energy store to the thermal energy stores of the brakes.
What is the relationship between kinetic energy and braking force?
Energy in the vehicle’s kinetic energy store = Work done by the brakes.
Fill in the blank: Energy in the vehicle’s kinetic energy store is calculated as _______.
½ x m x v²
What is the formula for calculating work done by the brakes?
Work done = F x d (where F is braking force and d is braking distance)
How does vehicle speed relate to the force needed to stop it?
As speed increases, the force needed to stop the vehicle within a certain distance also increases.
What can very large decelerations cause?
Very large decelerations can cause brakes to overheat and may lead to skidding.
True or False: The faster a vehicle is going, the less work needs to be done to stop it.
False
What is the mass of the car in the example provided?
1000 kg
At what speed is the car traveling in the example?
10 m/s
How far is the car from the hazard when the brakes are applied?
50 m
What is a typical reaction time range?
0.2 s - 0.9 s
What factors can affect an individual’s reaction time?
Everyone’s reaction time is different
What is one method to measure reaction times?
Ruler Drop Test
Describe the first step of the Ruler Drop Test.
Sit with your arm resting on the edge of a table.
What should you do after the ruler is dropped in the Ruler Drop Test?
Close your thumb and finger to try to catch the ruler as quickly as possible.
What does the measurement on the ruler represent in the Ruler Drop Test?
How far the ruler dropped in the time it took you to react.
What happens if the distance fallen is longer in the Ruler Drop Test?
The longer the distance, the longer the reaction time.
What is the equation to calculate reaction time from the Ruler Drop Test?
s = ut + 1/2 at^2
What is the value of acceleration due to gravity used in the reaction time equation?
9.8 m/s²
What are some ways to improve the accuracy of the Ruler Drop Test?
- Do a lot of repeats and calculate an average reaction time
- Add a blob of modelling clay to help the ruler fall straight down
- Use the same ruler for each repeat
True or False: You need to memorize the reaction time equation used in the Ruler Drop Test.
False
Fill in the blank: A typical reaction time can be measured using a _______.
computer-based test
Why might Mark’s thinking distance be longer when driving in the evening?
Less visibility and increased fatigue may affect reaction times.
What is the significance of catching the ruler at different distances during the test?
It helps determine the reaction time based on the distance fallen.
What does ‘s’ represent in the reaction time equation?
Distance fallen in metres
What does ‘t’ represent in the reaction time equation?
Reaction time in seconds
What does ‘a’ represent in the reaction time equation?
Acceleration due to gravity
What is the difference between scalar and vector quantities?
Scalar quantities have magnitude only, while vector quantities have both magnitude and direction.
True or false? Time is a vector quantity.
False
What is the difference between contact and non-contact forces?
Contact forces require physical interaction, while non-contact forces act at a distance.
True or false? Mass is a force measured in newtons.
False
What is the formula for calculating the weight of an object?
Weight = mass × gravity
What is the formula for calculating the work done by a force?
Work = force × distance
‘Force’ is applied in the direction of the displacement.
What is a resultant force?
The single force that has the same effect as all the individual forces acting on an object combined.
How many joules of work does 1 Nm equal?
1 Joule
What is the difference between elastic and inelastic deformation?
Elastic deformation returns to original shape after the force is removed, while inelastic deformation does not.
What is the limit of proportionality?
The maximum extent to which Hooke’s Law is valid, beyond which the material does not return to its original shape.
Give the equation that links force, extension, and the spring constant of an object.
Force = spring constant × extension
What is the difference between displacement and distance?
Displacement is the shortest path from the initial to the final position, while distance is the total path traveled.
Estimate the speed of a person walking.
Approximately 1.5 meters per second
Write down the equation that links acceleration, velocity, and time.
Acceleration = (final velocity - initial velocity) / time
For what type of acceleration can you use the equation v² - u² = 2as?
Uniform acceleration
What does the gradient represent for a distance-time graph?
Speed
What does the gradient represent for a velocity-time graph?
Acceleration
State Newton’s three laws of motion.
- An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a force.
- Force equals mass times acceleration.
- For every action, there is an equal and opposite reaction.
Describe an experiment that you could do to investigate Newton’s Second Law.
Use a cart on a track with varying weights and measure acceleration for different forces applied.
What is the stopping distance of a vehicle?
The total distance a vehicle travels from the point at which the driver perceives a need to stop to the point where the vehicle comes to a complete stop.
How can the stopping distance be calculated?
Stopping distance = thinking distance + braking distance
Give two things that affect a person’s reaction time.
- Age
- Distractions
State four things that can affect the braking distance of a vehicle.
- Speed of the vehicle
- Condition of the brakes
- Road conditions
- Tyre conditions
Explain why the temperature of a car’s brakes increases during braking.
Friction between the brake pads and discs converts kinetic energy into thermal energy.
What is a typical reaction time?
Approximately 0.2 to 0.3 seconds
Briefly describe an experiment you could do to compare people’s reaction times.
Drop a ruler and measure the distance it falls before being caught.
What is a medium in the context of wave propagation?
A substance through which waves travel.
In transverse waves, how do the particles move relative to the direction of wave propagation?
Perpendicular to the direction of wave propagation.
What is a characteristic of longitudinal waves?
Particles oscillate parallel to the direction of wave propagation.
What is a sound wave?
A longitudinal wave that travels through a medium, such as air or water.
Displacement is how far a particle is from its _______.
rest position
