Work done = force * distance
work done = 200 * 20
work done = 4000J
more deceleration.
in vertical motion downwards => terminal velocity ... raindrops etc
Answer: A piston-filling fountain pen has a piston — just like in a car — inside the barrel. This piston goes down to expel air or ink and then back up, pulling ink into the barrel. The typical process is very simple, assuming the pen is clean and dry: Push the piston down, expelling any air in the barrel
The centripetal force needed to keep earth in orbit is gravity.
