The rate of rotation of a solid disk with a radius of #8 m# and mass of #5 kg# constantly changes from #5 Hz# to #17 Hz#. If the change in rotational frequency occurs over #3 s#, what torque was applied to the disk?
1 Answer
Nov 11, 2017
Explanation:
Torque is rate of change of angular momentum.
#= (I2pi(f_f - f_i))/t#
#= ((mr^2)/2 2pi(f_f - f_i))/t# ………[∵ Moment of inertia of disc about is central axis is#(mr^2)/2# ]
#= (("5 kg × (8 m)"^2)/2 × 2 π (17 - 5) "Hz")/"3 s" = "4021.2 Nm"#