Hey!
First, let's write the problem.

Subtract the numbers, we would do the following operation,


Add 2 to both sides.

This tells us that our final answer would be,

Thanks!
-TetraFish
After 5 seconds the stone will have fallen 49 m
I think it might be a or d i hope i have helped :)
At the highest point: kinetic energy is 0 due to the speed is 0
So the total mechanical energy is 20
Assume no frictions present, then the mechanical energy is conserved
So at the lowest point, kinetic energy = mechanical energy - potential energy
Answer will be 20 - 0.5 = 19.5 J
Answer:
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