Motion and Forces

Question 1

What is a scalar quantity?

Answer 1

A quantity that has a magnitude (size) but no direction.

Question 2

What is a vector quantity?

Answer 2

A quantity that has a magnitude (size) and a direction

Question 3

Give some examples of vector quantities.

Answer 3

Force
Velocity
Displacement
Weight
Acceleration
Momentum

Question 4

Give some examples of scalar quantities.

Answer 4

Speed
Distance
Mass
Energy
Temperature
Time

Question 5

What is the difference between speed and velocity?

Answer 5

Speed is how fast you are going and has no direction whereas velocity is speed in a given direction

Question 6

1) Speed =
2) Distance =
3) Time =

Answer 6

1) Speed = Distance / Time
2) Distance = Speed x Time
3) Time = Distance / Speed

Question 7

Distance-Time Graph

Answer 7

https://www.google.com/url?sa=i&url=https%3A%2F%2Fmmerevise.co.uk%2Fgcse-maths-revision%2Fdistance-time-graphs-gcse-revision-and-worksheets%2F&psig=AOvVaw3204rYTjkbPoznMG3T00Z5&ust=1693570067450000&source=images&cd=vfe&opi=89978449&ved=0CA8QjRxqFwoTCMjEwqTuhoEDFQAAAAAdAAAAABAD

Question 8

How to calculate acceleration?

Answer 8

a = (v - u) / t
a = Acceleration
v = Final Velocity
u = Initial Velocity
t = Time

Question 9

How to calculate constant acceleration?

Answer 9

v^2 - u^2 = 2 x a x X
X = Distance

Question 10

Velocity-Time graph

Answer 10

https://www.google.com/url?sa=i&url=https%3A%2F%2Fmmerevise.co.uk%2Fgcse-maths-revision%2Fvelocity-time-graphs-gcse-revision-and-worksheets%2F&psig=AOvVaw2r3btrFg6LLShLPlH1C4qm&ust=1693571046157000&source=images&cd=vfe&opi=89978449&ved=0CA8QjRxqFwoTCPCKrPbxhoEDFQAAAAAdAAAAABAD

Question 11

How to calculate distance travelled from a distance-time graph?

Answer 11

Split the area under the graph into shapes and find the area for each shape and add them together.

Question 12

How can light gates measure speed and acceleration?

Answer 12

Speed:
The light gate sends a beam of light from one side of the gate to a detector on the other side. When something passes through the gate, the beam of light is interrupted. The light gates measure how long the beam was undetected.
To find the speed, connect the light gate to a computer.

Question 13

How can light gates measure speed and acceleration?

Answer 13

Acceleration:
Use an object that interrupts the signal twice in a short period of time. The light gates measures the speed for each section and calculates acceleration.

Question 15

What is Newton’s First Law?

Answer 15

If the resultant force on a stationary object is zero, the object will remain stationary.
If the resultant force on a moving object is zero, it’ll just carry on moving at the same velocity.

Question 16

What is Newton’s Second Law?

Answer 16

Larger the resultant force acting on the object, the more the object accelerates. Force and acceleration are directly proportional.
Acceleration is also inversely proportional to the mass of the object - Larger mass will accelerate less.
**Formula:*
F = m x a
F = Resultant force
m = Mass
a = Acceleration

Question 17

What is Weight?

Answer 17

The force acting on an object due to gravity.
Weight is a force measured in newtons.

Question 18

What is the formula for Weight?

Answer 18

Weight = mass x gravitational field strength
Gravitational field strength on earth is 10 N/kg

Question 19

How is weight measured?

Answer 19

Weight can be measured using a calibrated spring balance or a newton meter.

Question 21

Practical : Investigating the relationship between force, mass and acceleration by varying the masses added to trolleys

Answer 21

1. Measure mass of the trolley and the hanging hook. Measure the length of the piece of card which will interrupt the light gates
2. Adjust the height of the ramp until the trolley starts to move down by itself
3. Mark a line on the ramp just before the first light gate
4. Attach the trolley to the hanging mass using a string. Hold the trolley still at the start line and let go
5. Each light gate will record the time when the trolley passes through. The acceleration can be found out using acceleration = change in speed / time

Question 22

If a object is travelling at a constant speed, is the velocity changing?

Answer 22

No, if an object is travelling in a circle at a constant speed, it is constantly changing direction, so it is constantly changing velocity. This mean it’s constantly accelerating and there must be a resultant force acting on it.

Question 23

What is Centripetal force?

Answer 23

Force that keeps something moving in a circle.

Question 24

What is inertial mass?

Answer 24

Measures how difficult it is to change the velocity of an object. Inertial mass can be found using Newton’s second law rearranging to give m = f / a, this means it is just the ration of force over acceleration.

Question 25

What is Newton’s third law?

Answer 25

When two objects interact, the forces they exert on each other are equal and opposite.

Question 26

What is momentum?

Answer 26

Measure if the tendency of an object to keep moving - or of how hard it is to stop it moving.

Question 27

What is the formula for momentum?

Answer 27

p = m x v
p = Momentum (Kg m/s)
m = Mass
v = Velocity

Question 28

Describe momentum in collisions?

Answer 28

When moving objects collide the total momentum of both objects is the same before the collision, as long there are no external forces acting. This is know as Conservation of momentum

Question 29

Force =

Answer 29

Force = change in momentum / time

Question 30

Explain how you can measure a human’s reaction time?

Answer 30

One way to measure reaction time is through a computer test or using the ruler drop test.

Question 31

What is the formula for stopping distance?

Answer 31

Stopping distance = Thinking distance + Braking distance

Question 32

What are some factors that can affect the stopping distance?

Answer 32

Mass of the vehicle
Speed of the vehicle
Driver’s reaction time
State of the vehicle’s brakes
State of the road
Amount of friction between tyre and the road

Question 33

What are some factors that affect a driver’s reaction time?

Answer 33

Tiredness
Alcohol
Drugs
Distractions