Question

From the top of a builing , a ball is dropped, while another ball is projected horizontally at the same time, It is estimated that (i) two balls will strike the ground simultaneously, (ii) two balls will strike the ground with the same sped.
Read the above passage and answer the foolwing questions :
(i) Do you agree with the two statements ? ltbRgt (ii) How do you justify answer physically ?

Answer 1

(i) Two balls will strike the ground smltaneously . This is correct. But the second statement is wroun . Infact, the ball projected horizontally will hit the grond woth a greater speed than the ball ust dropped. ltbRgt (ii) The first statement is crrect because motions along horizontal and vertical directions are indepedn of eachothe, with no interplay. In both the casee, vertical is same (= + g). Therefore, time taken to strimke the ground is the same.
The second starement is wrong, because the body projected horizontally has been given some energy. Gravitational pull through the same height gives same energy to both. Hernce overall eneragy of body projected horizontally becomes more and hence it hits the gound with a greater speed than the ball just dropped.