3 - Motion

Question 1

What is the formula for average speed?

Answer 1

Vₐᵥ = Δx / Δt

Question 2

What is the formula for average acceleration?

Answer 2

a = Δv / Δt = (v / u)/t

Question 3

What is instantaneous velocity and what is it’s formula?

Answer 3

Instantaneous velocity (v) is the rate of change of
displacement with respect to time:

v = ds/dt = gradient of displacement-time graph

Question 4

What is instantaneous acceleration and what is it’s formula?

Answer 4

Instantaneous acceleration (a) is the rate of
change of velocity with respect time:

a = dv/dt = gradient of velocity-time graph

Question 5

What is deceleration?

Answer 5

Deceleration occurs when the magnitude of the velocity (can still be positive) is decreasing with time.

Question 6

What is the formula for thinking distance?

Answer 6

speed (ms⁻¹) x reaction time (s)

Question 7

What is the stopping distance?

Answer 7

Stopping distance = thinking distance + braking distance

Thinking distance = distance travelled after seeing a reason to stop prior to stopping

Braking distance = distance travelled from time the brake is applied until the vehicle stops