A track is made of a piece of channel iron bent as shown. A ball released at the left end of the track continues past the various points. Rank the speed of the ball at points A, B, C, and D, from fastest to slowest. (Watch for tie scores.)
Solution 2R Step 1 This is the path of the ball. When the ball is released above the top of A, the ball will acquire a velocity V at A. A Then later it will increase when it reaches to B as the slope increases after the point A. So, the velocity at B will be V . B As it reaches C, the velocity will be maximum since the slope increases in between B and C. So, the velocity at C will be V . C The velocity will then decreases since the ball moves from C to D. The velocity will be same as that of B when the ball reaches at D. It is because there is no height difference between the points B and D. So, V = V . B D The velocity from fastest to slowest would be, V > V = V CV B D A Conclusion The velocity will be same for same height. All these conditions are applicable only if the frictional force is negligible.
