An ideal gas at STP is first compressed until its volume is half ...

[Alygatorr01285]

An ideal gas at STP is first compressed until its volume is half the initial volume, and then it is allowed to expand until its pressure is half the initial pressure. All of this is done while holding the temperature constant.
 
  If the initial internal energy of the gas is U, the final internal energy of the gas will be A) U.
  B) 2U.
  C) U/2.
  D) U/3.
  E) U/4.

Question 2

Jennifer hits a stationary 200. gram ball and it leaves the racket at 40. m/s. If time lapse photography shows that the ball was in contact with the racket for 40. ms:
 
  (a) What average force was exerted on the racket?
  (b) What is the ratio of this force to the weight of the ball?

[soda0602]

Answer to Question 1

A

Answer to Question 2

(a) 0.20 kN
(b) 1.0  102

[Alygatorr01285]

Wow, this really help

[cici]

Gracias!