Question

If a bomb of mass 30 kg at rest explodes into two pieces of mass 12 kg and 18 kg. The velocity of 18 kg mass is 6 m/s, then the kinetic energy of other mass is

Answer 1

Initial momentum of bomb is 0 

after exploding the speed of mass 18 kg is 6 m/s and the speed of mass 12 be U

 

so momentum after collision = momentum 1 + momentum 2

P = 18 x 6 + 12 x U

P = 108 + 12 U

now according to conservation of momentum

momentum before collision = momentum after collision

o = 108 + 12 U

-108 = 12U

-108/12 = U

-9 = U

  

so KE = 1/2 m v square

KE = 1/2 x 12 x -9 square

KE = 486 J

Answer 2

Answer:

The K.E. of 12 kg mass will be 486 J