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?

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Answer 1 · 2016-01-20T11:46:08

Only the average torque can be calculated, which is #40.8 "Nm"#.

The angular inpulse is given by

#mR^2Delta omega = (3"kg")(2"m")^2(18"Hz"-1"Hz")#

#= 204"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"#.