Two students go to play basketball. They notice the ball is flat (it won't bounce). They decide to pump it up with air. a After it is pumped with air, will the ball have more, less, or the same amount of mass as before air was added?

b Cannot determine unless we measure the mass.

c The ball has more mass after being pumped with air.

d The ball has the same amount of mass after being pumped with air.

Justify your answer
The ball has less mass after being pumped with air.

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?