1.

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. 2.5JB. 5JC. 525JD. 640 J

Answer» Correct Answer - D
Using law of energy conservation,
`(TME)_(i) = (TME)_(f)implies U_i+ K_i = U_f + K_f`
`implies 20 xx 10 xx 3 + 1/2 xx 20 xx 2^(2)= 0+ K_fimplies K_f= 640 J`


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