Paper 1/ 2: Section 1- Motion, Forces and Conservation of Energy Flashcards
What is a scalar quantity? List a few examples:
Scalar quantity- quantities we can measure with only magnitude.
ex. Direction, speed, mass, temp and energy
What is a vector quantity? List a few examples:
Vector quantity- quantities with both magnitude and direction.
ex. Displacement, velocity, weight, acceleration and momentum
What is the definition of speed and how is it calculated?
Speed- the rate of which something moves/ operates.
S= D/ T
What is the definition of velocity and how is it calculated?
Velocity- the speed of something in a given direction
V= Displacement / Time taken
What is terminal velocity?
When the resultant force acting on it is zero, so the object moves at a steady speed in a constant direction.
List the general typical speed for:
Walking
Running
Wind
Cycling
Cars (in town)
Cars (on motorways)
- Walking= 1.5 m/s
- Running= 3 m/s
- Wind= 5-20 m/s
- Cycling= 5.5 m/s
- Cars (in town)= 13 m/s
- Cars (on motorways)= 31 m/s
What is the definition of acceleration and how is it calculated?
Acceleration- the change of velocity in a certain amount of time.
Final V (V)- Initial V (U) / T
What is uniform acceleration and how is it calculated?
Uniform acceleration- constant acceleration.
V^2- U^2 = 2 x a x X
List the general typical acceleration for:
Running
A rolercoster
A family saloon car
An F1 car
A parachutist
- Running= 3 m/s^2
- A rolercoster= 30-40 m/s^2
- A family saloon car= 7 m/s^2
- An F1 car= 49 m/s^2
- A parachutist= 200 m/s^2
What does a distance/ time graph tell us?
How far something has travelled.
List the motions of the object each part of a distance/ time graph represents:
Gradient (slope)
Flat sections
Steeper sections
Curved
. Steeper curve
. Levelling off curve
Gradient (slope)- speeding up
Flat sections- stopped
Steeper sections- faster
Curved- acceleration
. Steeper curve= speeding up (increasing gradient)
. Levelling off curve= slowing down (decreasing gradient)
What does a velocity/ time graph tell us?
How an object’s veocity changes over time.
List the motions of the object each part of a velocity/ time graph represents:
Gradient (slope)
Flat sections
Steeper sections
Uphill sections (/)
Downhill sections ()
Curved
Gradient (slope)- acceleration
Flat sections- steady speed
Steeper sections- the greater the acceleration or decceleration
Curved- changing acceleration
Uphill sections (/)- acceleration
Downhill sections ()- decceleration
What does the area under a velocity/ time graph equal time? How can you calculate the area (distance travelled) using this area?
The distance in that time interval.
. Distance travelled= split area and a triangle and rectangle, then add their areas.
How can you find the speed on a distance/ time graph?
Speed= gradient= change in the vertical/ change in the horizontal
Newtons 1st law: A _________ force is needed to make an object start ______, _____ up or ____ down.
- resultant
- moving
- speed
- slow
What happens when the resultant force on a stationary object is zero?
It remains stationary.
What happens when the resultant force on a moving object is zero?
It carrys on at the same velocity.
What is Newtons 2nd law?
The acceleration of an object is directly proportional to the resultant force and inversely proportional to the mass of the object.
Formula: F (N)= m (kg) x a (m/^2)
What is the definition of weight and how is it calculated?
Weight- A vector quantity, measuring the force acting on an object due to gravity.
W (N)= m x g’ravitational field strength’ (N/ kg)
What is the definition of mass and how is it calculated?
Mass- A scalar quantity, measuring the amount of ‘stuff’ in an object.
m= W/ g
What is Earth’s gravitational field strength?
10 N/ kg
What is the force that keeps smething moving in a circle called?
Centripetal force.
What is it ment by circular motion?
If an object is travelling in a circle at a constant speed, its constantly changing velocity (therefore direction too).
Newtons 3rd law: When two objects interact, the ______ they exert on eachother are _____ and ________.
- forces
- equal
- opposite
What is inertia an how can it be found?
Inertia- the tendancy for motion to remain unchanged (the same velocity)
. Can be found through Newtons 2nd law (F= mx a)
What is equilibrium?
When two opposite forces are acting on an object are equal.
What is momentum measured by and how is it calculated?
Momentum is measured as a product of its mass and velocity.
Momentum (kg m/s)= mass x velocity.
. p= m x v
The _______ the mass of an object, or the greater its ________, the ____ momentum the object has.
- greater
- velocity
- more
Forces cause changes in momentum: What is the equation for this concept?
Force= change in momentum (mv- mu)/ T
What is the conservation of momentum?
The total momentum before an event = the total momentum after.
What is stopping distance?
Stopping distance= thinking distance + breaking distance
What is thinking distance and what two main factors affect it?
Thinking distance- the distance taken to stop once the brakes have been applied.
Affected by your reaction time and your speed (the faster you’re going, the further you’ll travel).
What can increase your reaction time?
. Tiredness
. Alchol (depressants)
. Drugs (depressants)
. Distractions
What is braking distance and what four main factors affect it?
The braking distance is the distance it takes to stop once the brakes have been applied.
It can be affected by…
. Speed- the faster you go, the longer it takes to stop.
. Cars mass- won’t stop as quickly.
. Condition of brakes- worn or faulty brakes can’t brake with as much force.
. Friction between the tyres and road- less friction can lead to skidding.
. Bald tires or bad weather.
What are the eight energy stores and which things store their energy in each store?
Kinetic- anything moving has energy in this store.
Thermal- any object (the hotter, the more energy in this store).
Chemical- anything able to release energy by a chemical reaction.
GPE- anything in a gravitational field (ie. Things that can fall)
Elastic potential- anything stretched.
Electrostatic- Eg. Two charges that attract or repel eachother.
Magnetic- Eg. Two magnets that attract or repel eachother.
Nuclear- atomic nuclei release energy from this store in nuclear reactions.
How do you find a kinetic energy store?
KE (J)= 1/2 x m (kg) x v^2 (m/s^2)
Energy can be stored, _________ between stores, and __________- but it can never be _______ or _________.
- transferred
- dissipated
- created
- destroyed
What four main ways can energy be transferred between stores?
- Mechanically- a force acting on an object.
- Electrically- a charge doing work.
- By heating- energy transferred from a hotter object to a colder object.
- By radiation- energy transferred by waves.
In a diagram showing energy transfers, what does each part represent?
. The boxes represent stores
. The arrows show the transfers
List five important examples of energy transfers (understand them):
. A ball rolling up a slope
. A ball hitting a ball
. A rock dropped from a cliff
. A car slowing down (without braking)
. A kettle boiling water
How do you calculate the change in gravitational potential energy (GPE)?
GPE= m x g (N/kg) x h (m)
(g means gravitational field strength= N/ kg)
What is the ‘conservation of energy principle’?
Total energy input= useful energy output + wasted energy
The ____ energy that’s ______, the more ________ the device is said to be. The amount of energy that’s ______ can often be reduced.
- less
- wasted
- efficient
- wasted
How do you calculate efficiency?
Efficiency= useful energy transferred by device (J) / total energy supplied to device (J)
Finish the sentence: ‘Seeing as some energy is always wasted, the efficiency can never be equal to or higher than….’
1 (or 100%)
What are the main two ways you can reduce the amount of energy that’s wasted?
- Lubrication
- Thermal insulation
The diagram to show efficiency is called a Sankey diagram, what does each part represent?
. A horizontal arrow beginning with the ‘total energy supplied ‘
. The thickness of the arrows represents how much energy is being transferred.
. The point of the arrow shows the ‘useful energy’ transferred.
. ‘Wasted energy’ splits off with a downward, vertical arrow.
How does lubrication reduce energy transferred?
Lubricants are usually liquids, so they flow easily between objects and coat them. This reduces the friction between both surfaces when they move.
How does insulation reduce energy transferred?
In a building, the lower the thermal conductivity of its walls, the slower the rate of energy transfer through them. Thicker walls and outer walls with an air gap in the middle slows the rate of energy transfer.
What are the non- renewable energy resources?
Fossil fuels (coal, oil and natural gas) and nuclear fuel.
What are some renewable energy resources?
.Bio- fuels
. Wind
. The Sun (solar)
. Hydro- electricity
. Tides
Bio- fuels are _________ energy resources created from either _____ products or animal ____. They can be burnt to produce __________ or run ____ like fossil fuels.
- renewable
- plant
- dung
- electricity
- cars
List four renewable energy sources that don’t generate as much electricity as non- renewables though:
- Wind power
- Solar cells
- Hydro- electricity
- Tidal barrages
