<span>It acts as a sunscreen to </span>protect us<span> against UV radiation. </span>
Answer: Time to reach max. height is the time taken by it to reach the topmost position whereas time of flight is the overall time taken by it, i.e. till it reach down back to the thrower or launcher. And also time of flight is double the time to reach maximum height.
Explanation:
According to momentum conservation
15*3 = 45kgm/s
and the velocity of 5 kg mass will be
45/5 = 9 m/s