You already have the speed, now you need the time.
I will use the formula for speed which is S=D/T.
S=Speed D=Distance T=Time.
So here we have, 18m/s = 52m/T
we do 18 divided by 52 which would be .3461.
.3461 seconds is how long it took the stone to reach the water.
Answer:
figure out what the letter mean , the figure how it's worth
In a collision an object experiences a force for a specific amount of time, which results in a change momentum(the objects mass may ethier speed up or slow down). Impulse will be produced because of force appiled to an object over a period of time.