Question

A wheel starts from rest and rotates with constant angular acceleration to reach an angular speed of 12.9 rad/s in 2.98 s.

Answer 1

Explanation:

(a) Find the magnitude of the angular acceleration of the wheel.

• angular acceleration = angular speed /time
• angular acceleration = 12.9/2.98 = 4.329rad/s²

(b) Find the angle in radians through which it rotates in this time interval.

• angular speed = 2x3.14xf
• 12.9rad = 2 x3.14

• rad = 6.28/12.9
• rad = 0.487

Now we convert rad to angle

• 1 rad = 57.296°
• 0.487 = unknown angle
• unknown angle =57.296 x 0.487 = 27.9°

The angle in radians = 27.9°