AH 1.2 Angular Motion (Knowledge)

Question 1

For a body exhibiting unform circular motion, define angular velocity in words.

Answer 1

Angular velocity is the angle swept out by the body divided by the time taken

Question 2

Define angular velocity using symbols.

Answer 2

ω = ɵ/t

Question 3

State the equation for instantaneous angular velocity.

Answer 3

dω = dɵ/dt

Question 4

Stae the equation for instantaneous angular acceleration.

Answer 4

α = dω/dt = d₂ɵ/dt²

Question 5

What is required for uniform circular motion to take place?

Answer 5

An unbalanced force directed towards the centre of the described circle and acting on the body exhibiting circular motion.

(This is called a centripetal or radial force).

Question 6

State the equation for centripetal force and define each term with its unit.

Answer 6

F = mv²/r = mrω²

where

m = mass of body describing unifrom circular motion (kg)

v = linear tangential velcoity of body (ms-¹)

r = radius of described circle (m)

ω = angular velocity (rad s^-1)