Chapter 2: Kinematics

Question 1

What is distance?

Answer 1

The total length of the actual path travelled by a body

Question 2

What is displacement?

Answer 2

The distance of a body from a fixed point in a specific direction

Question 3

What is speed?

Answer 3

The rate of change of distance travelled with respect to time

Question 4

What is velocity?

Answer 4

The rate of change of displacement with respect to time

Question 5

What is acceleration?

Answer 5

The rate of change of velocity with respect to time

Question 6

Derive v = u + at

Answer 6

a = (v - u) / t
v = u + at

Question 7

Derive s = ut + ½at²

Answer 7

Since displacement is area under v-t graph,
∫ v dx = ½(v + u)t
s = ½(v + u)t

Sub v = u + at into above equation,
s = ½(u + at + u)t
s = ½(2u + at)t
s = ut + ½at²

Question 8

Derive v² = u² + 2as

Answer 8

With [a = (v - u)/t] and [s = ½(v + u)t],
a * s = ½(v - u)(v + u)
a * s = ½(v² - u²)
Rearranging, v² = u² + 2as

Question 9

What does it mean when a body is free falling?

Answer 9

When gravitational force is the only force acting on the body