Work Energy and Power - Result Question 49

52. A ball is thrown vertically downwards from a height of 20m with an initial velocity v0. It collides with the ground loses 50 percent of its energy in collision and rebounds to the same height. The initial velocity v0 is : [2015 RS] (Take g=10ms2 )

(a) 20ms1

(c) 10ms1

(b) 28ms1

(d) 14ms1

Show Answer

Answer:

Correct Answer: 52. (a)

Solution:

  1. (a) When ball collides with the ground it loses its 50 of energy

KEfKEi=1212mVf212mVi2=12

or VfVi=12

or, 2ghV02+2gh=12

or, 4gh=V02+2gh

V0=20ms1



NCERT Chapter Video Solution

Dual Pane