Neutrinos are very abundant in the universe (our sun for example produces them in huge amounts as as by-product of nuclear fusion). a recent discovery has given them a (tiny) amount of mass. discuss how this would/could change our view of whether the expansion of the universe is slowing or not. (hint: think about gravity and potential energy due to gravity)

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?