Revision1. Define:

1. Distance

2. Displacement

3. Speed

4. Velocity

5. Acceleration

6. Deceleration

2. List the equations of motion

Distance – time graphOn a distance time graph, distance is on the y-axis and time on the x-axis

The gradient of a distance-time graph is numerically equal to the speed.

p.28 comp. phy

Speed – time graphSpeed is on the y-axis and time on the x-axis.

The gradient is numerically equal to the acceleration.

The area under the graph is equal to the distance covered.

p.29 comp. phy.

Graphs of acceleration p.34

Free fallWhen a stone and a feather are dropped from the same height, the stone reaches the ground first. This is because of air resistance.

However, when there is no air resistance, the stone and the feather hit the ground at the same time. The stone and feather have the same acceleration.

This acceleration is called acceleration due to gravity (g).

LOCATION ACCELERATION DUE TO GRAVITY

Earth 9.8m/s2

Mars 3.7m/s2

The Moon 1.6m/s2

Venus 9.5m/s2

Jupiter 24.5m/s2

The Sun 275m/s2

Qns.

Terminal VelocityWhen an object is falling freely, it accelerates. Its speed increases as well.

Considering air resistance the object will reach a point when it stops accelerating. Its speed remains constant. This constant speed is called Terminal Velocity.

Terminal velocity is defined as: a constant speed that a free falling object acquires when air resistance is equal to the weight of the object.

Draw diagram*