# AP Physics B

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system consists of a steal beam of mass M 􏰀 68.4 kg and length L 􏰀 1.84 m, with a 39.0-kg
brass sphere attached at the right end of the rod, as shown below.
BA
a. Determine the moment of inertia of the system for rotation about an axis through the center of the steel beam (axis A).
b. Determine the moment of inertia of the system for rotation about an axis through one end of the beam (axis B).
c. Determine the constant horizontal force, F, that must be exerted on the brass sphere in order to produce an angular acceleration of the system such that 􏰅 􏰀 2􏱐 rads. F is exerted perpendic- ular to the steel beam, and the system rotates around axis B.
d. Consider part c. If the system started from rest, determine the linear velocity of the brass sphere after the force has been applied for 4.0 s.

• AP Physics B -

125, 130

• AP Physics B -

D

• AP Physics B -

I know this question is old. But for anyone looking it up now, here's how to do it.
Use the formula
I = 1/12ml^2