A block is given a brief push so that it slides up a ramp. After the block reaches its highest point, it slides back down, but the magnitude of its acceleration is less on the descent than on the ascent. Why?
Solution 20Q: There is difference in the magnitude of acceleration during descent and ascent motion due to frictional forces which changes its direction depending upon the direction of motion. Step 1 of 4 Concept: Frictional force also acts on the surface of the bodies in contact whenever their is relative motion between between the two bodies. Step 2 of 4 Figure below shows the free body diagram of the various forces acting on the block during its ascent motion. Frictional force ffacts downward along the plane when the block moves up the plane due to applied force F as shown in figure above. Weight of the body acts vertically downward, and it is resolve into two components as shown in figure.Taking positive direction of motion along up the plane and negative direction of motion along down the plane. Let co-efficient of friction be , then frictional force ff= N = mg cos Acceleration of the block during the ascent motion, a = Fmg(sin + cos……(1) 1 m