Question

A wheel has a radius of 33 cm and completes 12 revolutions in 1 minute. a) determine the angular velocity of the wheel in radians/second. b) If the wheel is moving for 5 minutes, how far does it travel?

Answer 1

a) The angular velocity is 0.4π radians/second ⇒1.25664 radians/second

b) The wheel travels 124.4071 meters in 5 minutes ⇒ 39.6π meters

Explanation:

The angular velocity ω = 2 π n ÷ t, where

• n is the number of revolution

• t is the time in second

The distance that moving by the angular velocity is d = ω r t, where

• r is the radius of the circle in meter

a)

∵ A wheel completes 12 revolutions in 1 minute

∴ n = 12

∴ t = 1 minute

→ Change the minute to seconds

∵ 1 minute = 60 seconds

∴ t = 60 seconds

→ Substitute n and t in the rule above

∵ ω = 2 (π) (12) ÷ 60

∴ ω = 24π ÷ 60

∴ ω = 0.4π radians/second

∴ The angular velocity is 0.4π radians/second ⇒1.25664 radians/second

b)

→ To find the distance in 5 minutes multiply ω by the radius by the time

∵ The wheel has a radius of 33 cm

∴ r = 33 cm

→ Change it to meter

∵ 1 m = 100 cm

∴ r = 33 ÷ 100 = 0.33 m

∵ t = 5 minutes

→ Change it to seconds

∴ t = 5 × 60 = 300 seconds

→ Substitute them in the rule of the distance above

∵ d = 0.4π (0.33) (300)

∴ d = 39.6π meters ⇒ 124.407 meters

∴ The wheel travels 124.4071 meters in 5 minutes ⇒ 39.6π meters