Question

A ball of mass 0.2 kg is thrown vertically upwards by applying a force by hand. If the hand moves 0.2 m while applying the force and the ball goes upto 2 m height further, find the magnitude of the force. (Consider `g=10m//s^2`).
A. 16 N
B. 20 N
C. 22 N
D. 4 N

Answer 1

Correct Answer - B
`0=u^(2)-2gh=u^(2)-2xx10xx2`
`u^(2)=40`
`u^(2)=0+2axx0.2rArr40=0.4arArra=100m//s^(2)`
`F=ma=0.2xx100=20N`