1. The coefficient of kinetic friction equals 0.400 between a horizontal surface and the bottoms of two blocks, as sketched below. What are the magnitude of the contact force, F, that each block exerts on the other block, and what is the magnitude of the acceleration, a, of these blocks along the surface (if one may take for the gravitational acceleration, g = 9.80 m/s2 downward, and neglecting any effects due to air resistance)? 72.ON 13,00 kg / 5.00 kg 2. A 20.0-kg box slides downward along a frictionless inclined plane that makes an angle of 30.0 with respect to the horizontal direction, as sketched below. What are the magnitude of the normal force, FN, exerted on the box by the plane, and the speed, v, of the box 0.500 s after it is released from rest? 20 0 kg 130.0 3. A 2.00-kg ball moves at a constant speed of 3.00 m/s in a vertical circle, with a radius of 0.600 m. What are the tensions, FT, in the (massless attached) string at the top of the circle, and at the bottom of the circle? E 0.600m F ? 0 2,00 k