2.1: Distance, Speed and Acceleration

Question 1

What is a force and what does it do?

Answer 1

A force is a push or a pull, and it changes the position, shape and motion of an object.

Question 2

What is the equation for speed?

Answer 2

Speed = Distance/Time

Question 3

What shows the difference between speed and velocity?

Answer 3

The direction of movement is clarified with velocity - speed is a scalar quantity, meaning it has magnitude but no sense of direction

Question 4

What is the equation for velocity?

Answer 4

Velocity = Displacement/Time

Question 5

Define a Scalar.

Answer 5

Measurements that have a magnitude (size).

Question 6

Define a Vector.

Answer 6

Measurements that have size and direction. Velocity is a vector quantity.

Question 7

What is the equation for acceleration?

Answer 7

Acceleration = Change in Velocity/Time

Question 8

What is a speed-time graph?

Answer 8

A speed-time graph shows the motion of an object through a certain period of time. A straight line upwards or downwards represents a constant speed, a curve showing gradual acceleration and a flat horizontal line showing it stationary.

Question 9

What is a velocity-time graph?

Answer 9

A velocity-time graph shows the motion of an object in one direction through a certain period of time. A straight line upwards or downwards represents a constant speed, a curve showing gradual acceleration and a flat horizontal line showing it stationary.

Question 10

What does the area under a velocity-time graph represent?

Answer 10

The distance travelled

Question 11

How do we calculate stopping distance?

Answer 11

Thinking distance + braking distance

Question 12

When has a vehicle stopped?

Answer 12

When its speed is 0m/s

Question 13

What increases more significantly in stopping times when extra speed is added?

Answer 13

Braking distance, although thinking distance goes up too

Question 14

Name four factors that affect stopping distances

Answer 14

The velocity of the car
The reaction time of the driver
Whether the driver is distracted
The condition of the tyres

Question 15

What is the equation for resultant force?

Answer 15

F (N) = change in momentum (kg m/s) / time for change (s)

Question 16

What are the two ways of reducing the force on the occupants?

Answer 16

By reducing the speed of the collision and so reducing the change of momentum
By increasing the time for the collision

Question 17

What is speed?

Answer 17

A measure of how fast an object is moving

Question 18

Why is speed a scalar quantity?

Answer 18

Because it only has magnitude

Question 19

Why is velocity a vector?

Answer 19

Because it has direction as well as magnitude

Question 20

What is velocity measured in?

Answer 20

Metres per second, and in a specific direction

Question 21

What is accelaration?

Answer 21

The rate of change of velocity

Question 22

What is the equation for accelaration?

Answer 22

Acceleration = change in velocity/ time

Question 23

What are the units of accelaration?

Answer 23

Metres per second squared

Question 24

How can the speed of an object be found?

Answer 24

By measuring the gradient of the graph

Question 25

How do you work out the gradient?

Answer 25

The difference in height (y coordinates), divided by the difference in width (x coordinates)

Question 26

What is the area under a velocity time graph?

Answer 26

The distance travelled

Question 27

What does the safe stopping distance of a vehicle depend on?

Answer 27

The driver’s reaction time and the braking distance of the vehicle

Question 28

What do traffic control measures include?

Answer 28

Speed limits and speed bumps

Question 29

What value does speed but not velocity always have

Answer 29

A positive one