A bomb of mass 12 kilogram initially at rest ,explode into pieces of masses 4 kilogram and 8 kilogram. The speed of 8 kilogram is 6 meter per second. Then kinetic energy of 4 kilogram mass is

Answer 1

We can use conservation of momentum to find the speed of the 4 kg mass, and then use kinetic energy formula to find its kinetic energy.

Let v be the speed of the 4 kg mass after the explosion. Conservation of momentum gives:

12 kg * 0 m/s = 4 kg * v + 8 kg * 6 m/s

Simplifying:

0 = 4 kg * v + 48 kg*m/s

-48 kg*m/s = 4 kg * v

v = -12 m/s (note: the negative sign means the 4 kg mass is moving in the opposite direction to the 8 kg mass)

Now we can find the kinetic energy of the 4 kg mass using:

Kinetic energy = 1/2 * mass * velocity^2

Kinetic energy = 1/2 * 4 kg * (-12 m/s)^2

Kinetic energy = 288 J

Therefore, the kinetic energy of the 4 kg mass is 288 Joules.