Module 3.1 - Motion

Question 1

Define displacement

Answer 1

Distance moved in a particular direction from a reference point

Question 2

Define instantaneous speed

Answer 2

The speed at an actual point in time during a journey. This value changes at various points in a journey.

Question 3

Define average speed

Answer 3

The total distance travelled divided by the total time taken for a journey. These values do not change.

Question 4

Define velocity

Answer 4

Displacement per unit time

Question 5

Define acceleration

Answer 5

Change in velocity per unit time

Question 6

What does a straight diagonal line represent on a displacement-time graph?

Answer 6

Constant velocity

Question 7

What does a flat, horizontal line represent on a displacement-time graph?

Answer 7

A stationary object - zero velocity

Question 8

What does a curve (inwards) of increasing positive gradient represent on a displacement-time graph?

Answer 8

The object is accelerating

Question 9

What does a curve (outwards) with decreasing positive gradient represent on a displacement-time graph?

Answer 9

An object decelerating

Question 10

What does a flat, horizontal line on a velocity-time graph represent?

Answer 10

Constant velocity

Question 11

What does a flat, horizontal line at y=0 on a velocity-time graph represent?

Answer 11

A stationary object

Question 12

What does a flat, diagonal line represent on a velocity-time graphs?

Answer 12

Constant acceleration

Question 13

What does a curve on a velocity-time graph represent?

Answer 13

Non-uniform acceleration

Question 14

How do you work out displacement on a velocity-time graph?

Answer 14

Area under the graph

Question 15

What is the suvat equation involving: a, t, u and v?

Answer 15

v = u + at

Question 16

What is the suvat equation involving: u, s, t and v?

Answer 16

S = 1/2(v + u)t

Question 17

What is the suvat equation involving: a, t, u and s?

Answer 17

S = ut + 1/2at^2

Question 18

What is the suvat equation involving: a, t, s and v?

Answer 18

s = vt - 1/2at^2

Question 19

What is the suvat equation involving: a, v, u and s?

Answer 19

v^2 = u^2 + 2as

Question 20

What is acceleration due to free fall, g?

Answer 20

Acceleration of a body due to a gravitational field, with air resistance being ignored - 9.81 N/kg

Question 21

Why do objects of different masses fall at the same rate?

Answer 21

Although the objects with different masses will have different magnitudes of gravitational forces acting on them, the proportion of forces to masses is the same which means the acceleration due to free fall is also the same.

Question 22

What is thinking distance?

Answer 22

The distance the car travels between the driver seeing the hazard and applying the brakes.

Question 23

What 5 factors affect thinking distance?

Answer 23

> Higher speed
> Tiredness
> Alcohol and drugs 
> Distractions
> Age of driver

Question 24

What is the braking distance?

Answer 24

The distance the car travels between applying the brakes to rest.

Question 25

What 5 factors affect braking distance?

Answer 25

``` > Higher speed > Poor road conditions > Poor condition of brakes > Poor conditions of tyres > Mass of car (people/luggage) ```

Question 26

How do you work out thinking distance?

Answer 26

Reaction time(s) x Speed of car(m/s)

Question 27

What is the thinking distance and braking distance for a car at 20mph?

Answer 27

> T: 6m | > B: 6m

Question 28

What is the thinking distance and braking distance for a car at 30mph?

Answer 28

> T: 9 | > B: 14

Question 29

What is the thinking distance and braking distance for a car at 40mph?

Answer 29

> T: 12m | > B: 24m

Question 30

What is the thinking distance and braking distance for a car at 50mph?

Answer 30

> T: 15m | > B: 38m

Question 31

What is the thinking distance and braking distance for a car at 60mph?

Answer 31

> T: 18m | > B: 55m

Question 32

What is the thinking distance and braking distance for a car at 70mph?

Answer 32

> T: 21m | > B: 75m

Question 33

What is one mile in m?

Answer 33

1609.3m

Question 34

What is one mph in m/s?

Answer 34

1609.3 ÷ 3600 = 0.447m/s