A 2-kg ball slides on a curved wire, starting from rest at…

 A 2-kg ball slides on a curved wire, starting from rest at point A.  The segment from A to B is rough (i.e. it has friction!) and the segment from B to C is frictionless.  Find the speed of the ball at B if the ball comes to rest (momentarily) at C. (select closest answer)

A roller-coaster has a mass of 400 kg when fully loaded with…

A roller-coaster has a mass of 400 kg when fully loaded with passengers.  At the bottom of a circular dip of radius 60m (as shown in the figure) the car has a speed of 14 m/s.  What is the magnitude of the force of the track on the car at the bottom of the dip?

 (Extra Credit  worth 5 points):  All of the above objects h…

 (Extra Credit  worth 5 points):  All of the above objects have the same mass M, and the same radial distance R from the axis of rotation as shown.  Which two objects have the same moment of inertia about the central axis? (Select a correct answer and show work to prove why!)

Four masses are placed at the vertices of a rectangle (4 m x…

Four masses are placed at the vertices of a rectangle (4 m x 5 m) and held in those positions by four “light” (massless) rods which form the sides of the rectangle.  What is the moment of inertia of this rigid body about an axis (in red as shown) that passes through the rectangle at x = 3m? (Select closest answer)