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.

Answer 1

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