question_answer 46)

                   In a shotput event an athlete throws the shotput of mass 10 kg with an initial speed of \[1\,m\,{{s}^{-1}}\]at \[{{45}^{o}}\] from a height 1.5 in above ground. Assuming air resistance to be negligible and acceleration due to gravity to be \[10m\,{{s}^{-2}}\], the kinetic energy of the shotput when it just reaches the ground will be                 (a) 2.5 J                                 (b) 5.0 J                 (c) 52.5 J                               (d) 155.0 J                

Answer:

                  (d) \[K.E.=\frac{1}{2}m\times 2gh=mgh\]