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InterviewSolution
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In a shotput event an athlete throws the shotput of mass 20 kg with an initial speed of `2 m s^(-1)` at `45^@` from height 3 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be `10 m s^(-2)`, the kinetic energy of the shotput when it just reaches the ground will beA. 2.5 JB. 5.0 JC. 52.5 JD. 155.0 J |
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Answer» Correct Answer - D Initial KE of the shotput `=1/2(10 kg) (1 m//s^2)=5 J` Initial PE of the shotput at a height 1.5 m above ground `=mgh = (10 kg) (10 m//s^2) (1.5 m)=150 J` Total initial energy of the shotput = 155 J Since air resistance is negligible and final potential of the shotput as it hits the ground (h= 0) is zero, kinetic energy of the shotput on hitting the ground =155 J |
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