Led bullet of mass 50kg is fired with a velocity of 200m/s into a led block of mass 950g .given that the led block can move freely calculate (1)The kinetic energy after impact (2)the loss of energy.
that's "lead" not "led" in this context.
That's some bullet! 50kg? Really? Given the small mass of the block, I will assume that the bullet has mass 50g, not 50kg. Otherwise the block will present virtually no obstacle.
So. conserve momentum.
0.050*200 = (0.050 + 0.950)v
v = 10 m/s
KE before: 1/2 * 0.050 * 200^2 = 1000 J
KE after: 1/2 * 1 * 10^2 = 50J