A block of mass m = 4.70 kg is released from rest from point circled A and slides on the frictionless track shown in the figure below. (Assume ha = 7.50 m.) An illustration shows a wavy track, starting from a crest, moving to a trough, then again to a crest and trough, and finally to a crest that then moves downward. Three points in the track are highlighted, A, B, and C. Point A is at the top of the track where a block of mass m is placed ready to get released. It is at the height labeled ha from the ground. Point B is shown at the next crest and is at a height of 3.20 meters from the ground. Point C is shown at the following trough and is at a height of 2.00 meters from the ground. (a) Determine the block's speed at points circled B and circled C. point circled B m/s point circled C m/s (b) Determine the net work done by the gravitational force on the block as it moves from point circled A to point circled C. J