Question 2: i believe it's half life decay
question 3: relative dating
Answer:
A) If the paintball stops completely the magnitude of the change in the paintball’s momentum is 
B) If the paintball bounces off its target and afterward moves in the opposite direction with the same speed, the change in the paintball’s momentum is 
C) A paintball bouncing off your skin in the opposite direction with the same speed hurts more than a paintball exploding upon your skin because of the strength exerted is twice than if it explodes.
Explanation:
Hi
A) We use the formula of momentum
, so we have 
B) We use the same formula above, then due we have a change of direction at the same speed, therefore the change in the momentum is the double so
.
C) The average strength of the force an object exerts during impact is determined by the amount the object’s momentum changes. therefore
, as we don't have any data about the impact time but we know momentum is twice, time does no matter and strength is twice too.
The question is poorly written.
ALL of the choices cause a change in something.
A). Force causes a change in velocity.
B). and C). Power and energy cause changes requiring work.
D). Impulse causes a change in momentum.
The answer is wave.
A wave can be defined as a rhythmic flow that moves over a medium from one place to the different area.