Question

question no.39and40solution please

Answer 1

39) In y-direction, it has accelerated motion and in the x-direction, it has a constant speed u cosA where A is angle of projection.Average velocity in x-direction will be u cosA as average of any constant is constant itself. In y-direction net displacement will be zero and hence avg velocity zero.so net avg velocity is ucosA only.
40) Sol. During the motion of bomb its horizontal velocity u remains constant and is same as that of aeroplane at every point of its path. Suppose the bomb explode i.e. reach the ground in time t. Distance travelled in horizontal direction by bomb = ut = the distance travelled by aeroplane. So bomb explode vertically below the aeroplane. Suppose the aeroplane move making angle θ with horizontal. For both bomb and aeroplane, horizontal distance is u cos θ t. t is time for bomb to reach the ground. So in this case also, the bomb will explode vertically below aeroplane