Question

Hi, please explai the answer for all three part of the quesitons, espcially for part a, why can't you increase mass on both blcosk, since the eqaution from work- energy theory proves that 1/2 m r'2 = mgh , the mass doesn't really matter ??

Block A Block B M H Side View A track consists of a frictionless arc XY, which is a quarter-circle of radius R, and a rough horizontal section YZ, which has s kinetic coefficient of friction u. Both blocks initially have a mass of M. A student released Block A from rest at point X. It slides down the carved section of the track, and collides instantaneously and inelastically with block B at point Y. The two blocks move together to the right, sliding to point P, which is a distance from point Y. (a) The student has two additional masses of M/2 which will be added to the blocks. If the students want the combined blocks to slide the farthest past point P, on which block(s) should the masses be added? - Both on block A -Both on block B - One each on block B and block A Briefly explain your reasoning without manipulating equations.

Answer 1

a) At the point of collision,conservation of momentum takes place.If the student wants the combined block to move the farthest,it must have large velocity right after the collision.The combined mass will have a mass of 3M.whatever the students choice will be,but to get highest velocity,he must give block A (M) and no mass to block B so that incoming mass has highet value of momentum.

b) No,the post collision velocity is totally wrong.First of all the masses are not balanced in the equation for Vc.The equation suggested will definetly give highest velocity but the masses have been included wrongly.As I've already said highest velocity will be acheived when block A is given additional mass of M.(M/2 and M/2).

c) After all the corrections are made and if the student found that combined block dont move the farthest,the only possibility is that he didnt take into account the fact that kinetic friction changes with the increase in massThe value of.Kinetic friction is more if the weight of the block is more and vice-versa