Question

# Problem 5. Let's solve a modified version of a problem from Problem set #8.A bullet of mass m and speed v is fired horizontally and passes completely through a pendulum

bob of mass M. The bullet emerges with a speed of . The pendulum bob is suspended by a stiff rod of length d and mass M. So in this version of the problem, the mass of the rod is NOT negligible.This means that linear momentum conservation does not apply. It works in the earlier problem since the masses were basically point masses. In this more general case, it is angular momentum which is conserved. When the collision occurs, the pendulum is forced to rotate so its moment of inertia matters. (a) What is the angular momentum of the bullet-bob system about the pivot point? (b) What is the angular velocity of the pendulum after the collision? Problem 5. Let's solve a modified version of a problem from Problem set #8.A bullet of mass m and speed v is fired horizontally and passes completely through a pendulumbob of mass M. The bullet emerges with a speed of . The pendulum bob is suspended by a stiff rodof length d and mass M. So in this version of the problem, the mass of the rod is NOT negligible.This means that linear mnomentum conservation does not apply. It works in the earlier problemsince the masses were basically point masses. In this more general case, it is angular momentumwhich is conserved. When the collision occurs, the pendulum is forced to rotate so its momentof inertia matters. (a) What is the angular momentum of the bullet-bob system about the pivotpoint? (b) What is the angular velocity of the pendulum after the collision?

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