Question

the energy of a particle moving at 5m per sec is 125J.Its mass is

Answer 1

here the energy is obtained by motion of objects.hence the energy posses here by object is kinetic

so ,   Ke= 1/2mv²
 here we need to find mass

          Ke=1/2mv²
          125=1/2×m×5²

         125=1/2×m×25

         125×2=25m

           250=25m

          250/25=m

            10=m

hence the mass is 10kg