Momentum is conserved if and only if sum of all forces which are exserted on system equals zero. In our situation there are only internal forces, so by Newton's third law their vector sum is 0.
So
.
Kinetic energy of system at first:
. After:
. The secret is that other energy is in work of deformation forces (they in turn heat a bullet and a block).
Answer is A)
Answer:

Explanation:
The momentum change is defined as:

Taking the downward motion as negative and the upward motion as positive, we have:

Replacing (2) and (3) in (1):

So we have a structured form, but can still move. If we had a cell wall we would be stiff objects since it’s just a cell membrane we can still have movement
Answer:
Pressure = 5 x 10⁶ Pa
Explanation:
Given:
Height of building = 512 m
Find:
Pressure
Computation:
P2 = P1+dgh
P2 = 1 + (1000)(9.8)(512)
P2 = 51.2 atm
Pressure = 5 x 10⁶ Pa