Answer:
a)
, b) 
Explanation:
a) The potential energy is:



b) Maximum final speed:

The final speed is:


Force exerted by the bullet = mass * acceleration = 0.013 * 850 = 11.05 Newtons.
the rifle exerts same force in opposite direction so we have
11.05 = 3.5 * a
acceleration = 11.05 / 3.5 = 3.16 m /s^-2
Answer:
Pressure on both feet will be
Explanation:
Weight of the person F = 500 N
Area of foot print 
Area of both the foot 
We have to find pressure on both the feet
Pressure is equal to ratio of force and area
So pressure 

So the pressure on both feet will be
when person stands on both feet.
Look at the first person’s answer. Cause I know I’m wrong