The figure above gives the torque t that acts on an initially stationary disk that can rotate about its center like a merry-go-round. (The vertical axis is marked in increments of 1.5 N·m.) he figure above gives the torque t that acts on an initially stationary disk that can rotate about its center like a merry-go-round. (The vertical axis is marked in increments of 1.5 Nm.) What is the angular momentum of the disk about the rotation axis at each of the following times? answers are in kgm^2/s (a) t = 9.0 s (b) t = 18 s
Explanation / Answer
a) The angular momentum at time t= 9.0 s is L = (3 x 2 ) + (1/2)(3)(2) +(9 x 7) + (1/2)(3)(1) Area of the graph = 6 + 3+63+ 1.5 = 73.5 kg.m2/s2 b) at t= 18.0s L = (1/2)(9)(3) + (9)(6) = 67.5 kg.m2/s2