# An object with a mass of 3 "kg" is traveling in a circular path of a radius of 2 "m". If the object's angular velocity changes from 1 "Hz" to 18 "Hz" in  5 "s", what torque was applied to the object?

Jan 20, 2016

Only the average torque can be calculated, which is $40.8 \text{Nm}$.

#### Explanation:

The angular inpulse is given by

$m {R}^{2} \Delta \omega = \left(3 \text{kg")(2"m")^2(18"Hz"-1"Hz}\right)$

$= 204 {\text{kgm"^2"s}}^{- 1}$.

If you are asked to find torque, you must assume that the angular acceleration is constant. In that case, the torque is given by

frac{204"kgm"^2"s"^{-1}}{5"s"} = 40.8"Nm".