When an astronaut travels from the earth to the moon, her weight changes, but her mass remains constant. <em>(C ).</em>
It depends on how you want to solve it you can solve it in many different meathods:$
Initially, the velocity vector is
. At the same height, the x-value of the vector will be the same, and the y-value will be opposite (assuming no air resistance). Assuming perfect reflection off the ground, the velocity vector is the same. After 0.2 seconds at 9.8 seconds, the y-value has decreased by
, so the velocity is
.
Converting back to direction and magnitude, we get 