Forces and motion

Question 1

What is thinking distance

Answer 1

Distance travelled between the moment you first see a reason to stop, to the moment you use the brake. Given by the formula: Speed * Reaction time.

Question 2

What is breaking distance

Answer 2

Distance travelled from the time the brake is applied until the vehicle stops.

Question 3

What is stopping distance

Answer 3

Thinking Distance + Breaking distance.

Question 4

How can you calculate average speed

Answer 4

Distance travelled / Time taken

Question 5

What are the details of a distance-time graph

Answer 5

Distance is plotted on the Y-axis
Time is plotted on the X-axis
Speed = gradient of graph (Change in Y over Change in X)
A stationary object is shown by a horizontal straight line.
An object moving at constant speed is shown by a straight sloping line.
Instantaneous speed is calculated by the gradient of a tangent to a point in the graph.

Question 6

What are the details of a displacement - Time Graph

Answer 6

Displacement is plotted on the Y-Axis
Time is plotted on the X-axis
Velocity = Gradient of Graph
A stationary object is shown by a horizontal straight line.
A constant velocity is shown by a straight sloping line.
Instantaneous velocity is calculated by the gradient of a tangent to a point in the graph.
A negative gradient indicates object is returning to starting position.

Question 7

How to calculate average velocity

Answer 7

Change in Displacement / Time taken
If going to and from, displacement is 0 therefore velocity is 0

Question 8

How to calculate acceleration of an object

Answer 8

Change in Velocity / Change in time

Question 9

What are the details of a Velocity - Time graph

Answer 9

Velocity is plotted on the Y-Axis
Time is plotted on the X-Axis
Acceleration = Gradient of tangent to graph
Straight line of positive gradient = Constant Accelerations
Straight horizontal line = Constant velocity / 0 acceleration
Straight line of negative gradient = Constant Deceleration
Curve = Changing acceleration
Area under graph = Displacement
If non linear graph, count squares under graph

Question 10

What must you know about projectile motion

Answer 10

The horizontal velocity is always constant, calculated using speed = distance/time. Vertical velocity changes due to gravity. Initial vertical velocity is vsin(angle to the horizontal). Vertical velocity at max height is 0. Doubling time taken to reach max height gives total time of motion.