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:
The coefficient of static friction between your partner and the floor is 0.55
Explanation:
Given:
Mass 
Kg
Frictional force 
N
From the formula of frictional force,
Where 
coefficient of static friction, 
Put the above values and find the coefficient of static friction.
Therefore, the coefficient of static friction between your partner and the floor is 0.55
To solve this problem, we are going to use the formula for
work which is Fd where x and y are measured separately.
X direction: W = 13.5 x 230 = 3105 Joules
Y direction: W = -14.3 x -165 = 2360 Joules
So the total work is getting the sum of the two: 3105 + 2360
= 5465 Joules
25g of mass will require 25g of opposite force on the ball from the road and opposition is moving upward to work on the ball
P = 10^5 - ρ (average)gh
where ρ (average) = average air density between 0 and 5000 m = (1.22+0.74)/2 = 0.98
we know g & h
I get P = 52470 Pa
