How to find angular momentum from a graph

Question

I have been give a time v torque graph and asked to determine the change in angular momentum.

My textbook does not go over this and my professor hasn’t cover this.

Answer 1

If the angular momentum H is changing at a constant rate in time t, the torque τ is

τ = ΔH / Δt

So if you know the torque from the graph, you can get the change in H from

ΔH = τΔt

However, the question seems strange, because it is more likely that you would be given a straight line plot of H vs. t, and then you figure out the torque from the slope of the line. Please check the wording of the original question.

Note: If the rate of change of the angular momentum is not constant, you have a more complicated problem.