<span>The purpose of pumping is to increase overall velocity. The person drops down into a crouch while traversing the more-or-less flat bottom of the U-shaped pipe or bowl. Then, as he enters the sloped part of the ramp or bowl, called the transition, he straightens his legs and rises up. By raising his center of mass just at the beginning of the arc, the person gains energy and thereby increases his speed.</span>
Answer:
It's used to indicate pressure
Answer:
Net force will be 4.875 N
Explanation:
We have given mass of the cart m = 1.5 kg
Initial velocity of the cart = 0.2 m/sec
And final velocity of the car = - 0.125 m/sec ( Negative direction is due to opposite direction )
Instant of time 
Change in momentum is given by

Now force is given by

Net force will be 4.875 N
<span>A gymnast with mass m1 = 43 kg is on a balance beam that sits on (but is not attached to) two supports. The beam has a mass m2 = 115 kg and length L = 5 m. Each support is 1/3 of the way from each end. Initially the gymnast stands at the left end of the beam.
1)What is the force the left support exerts on the beam?
2)What is the force the right support exerts on the beam?
3)How much extra mass could the gymnast hold before the beam begins to tip?
Now the gymnast (not holding any additional mass) walks directly above the right support.
4)What is the force the left support exerts on the beam?
5)What is the force the right support exerts on the beam?</span>