Chapter 2- Kinematics

Question 1

Examples of vector quantities

Answer 1

Displacement 
Velocity 
Weight 
Acceleration 
Force 
Moment of a force

Question 2

Define speed

Answer 2

Speed is defined as the rate of change of distance of an object at a specific instant

Question 3

Define velocity

Answer 3

Velocity is defined as the rate of change of displacement of an object at a specific instant

Question 4

Define acceleration

Answer 4

Acceleration is defined as the rate of change of velocity (change in velocity over time taken)

Question 5

Define uniform acceleration

Answer 5

An object has uniform acceleration when it’s velocity increases by the same value every second

Question 6

Define free fall

Answer 6

A free falling object is one that falls under the sole influence of gravity (without air resistance)

All objects in free fall near the surface of the earth experience an acceleration of 10ms-1

Question 7

If an object is dropped from a height…

Answer 7

Initial velocity is zero

Question 8

If an object is projected upwards in a vertical direction…

Answer 8

• velocity is 0 at highest point of motion
• velocity at which it is projected is equal in magnitude and opposite in direction to the velocity that it has when it returns to the same height

Question 9

Eqns of motion

Answer 9

Eqns of motion are only applicable form motion with uniform acceleration (eg free fall)

Question 10

State the four equations of motion

Answer 10

1) v=u+at
2) v^2=u^2+2as
3) s=ut+1/2at^2
4) s= (u+v)/2 t or t(average v)

Question 11

Define Vector quantities

Answer 11

Vector quantities are quantities that have both magnitude and direction

Question 12

Distance time graph

Answer 12

Gradient represent speed

Area under graph: NA

Question 13

Displacement time graph

Answer 13

Gradient represents velocity

Area under graph: NA

Question 14

Speed time graph

Answer 14

Gradient represents
If motion in straight line in one direction: acceleration
Otherwise: magnitude of acceleration

Area under graph: Distance (positive value)

Question 15

Velocity time graph

Answer 15

Gradient represents acceleration

Area under graph represents displacement (can be positive or negative value)

Question 16

Define distance

Answer 16

Distance is a scalar quantity that refers to “how much ground an object has covered” during its motion

Question 17

Define displacement

Answer 17

Displacement is a vector quantity that refers to “how far out of place an object is”, it is the object’s overall change in position

Question 18

When is velocity constant?

Answer 18

The magnitude and direction of velocity has to be constant for velocity to be constant

Question 19

Velocity for anything moving in circles

Answer 19

Since the direction of velocity is continually changing, velocity is continually changing. Therefore acceleration, the rate of change of velocity, is not zero.