2. [Giancoli5 8.P.040.] A grinding wheel is a uniform cylinder with a radius of 8.20 cm and a mass of 0.560 kg.
(a) Calculate its moment of inertia about its center. [2] kg · m2 (b) Calculate the applied torque needed to accelerate it from rest to 1400 rpm in 4.00 s if it is known to slow down from 1400 rpm to rest in 55.0 s. [2] m · N
3. The picture below shows a ladder leaned against a wall with a paint can sitting on it. Draw a force diagram for the ladder. Note that the top of the ladder has rollers so there is no friction between the wall and the ladder. Use the following to describe each type of force: "N" for normal forces, "Ff" for frictional forces, and "Fg" for forces of gravity. Always refer to the left hand surface as the "wall" and the bottom surface as the "ground", refer to the paint can as "paint". Be sure to name all vectors correctly using the scheme above. Also note that these names are case sensitive, so use the provided names exactly as they appear.
In the answer boxes below, enter the vector sum of the forces and the torques acting on the ladder. Use the following symbols when creating symbolic answers. Also note that the paint can is a distance of (5/8)*L up the ladder, and the center of mass is a distance of (1/2)*L up the ladder. Assume that the pivot point is where the ladder meets the ground. Note: you may use sin() and cos() in your answer, but the angle must be in radians.
Return to Assignments Summary