M An astronaut on a planet with no atmosphere is conducting gravity experiments. He throws a large rock
upward with an initial speed of 2.0 and catches it after 4.0 s. The magnitude of the gravitational force
of the rock is 8.0 N.
S
What is the best estimate of the mass of the rock?

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?