Throcky skateboards down a frictionless circular ramp. He moves through a quarter circle with radius R = 3.00 m. Throcky and his skateboard have a total mass of m = 25.0 kg, (a) Find his speed at the bottom of the ramp. (b) Find the normal force that acts on him at the bottom of the curve. (c) Suppose that the ramp is not frictionless, and that Throcky's speed at the bottom is only 6.00 m/s, not the 7.67 m/s we found there. What work was done on him by the friction force? (a) At point (1) (b)