I think the answer is:
B) oceanic crust-continental crust
Hi there!
For this part, we can disregard the horizontal velocity because horizontal and vertical motion are INDEPENDENT.
We can used the simplified equation to solve for time:

Where:
h = height
g = acceleration due to gravity (assume g = 10 m/s²)
Plug in given values:

t ≈3.162 sec
Answer:
50 N
Explanation:
Since the refrigerator doesn’t move, that means the force of friction equals the amount of force the child exerts on the fridge. If the friction force were greater than the force by the child, the fridge would start accelerating towards the child. If it were less than the force the child exerted, the fridge would start accelerating away from the child. Therefore, the net force must be 0, in this case, the friction force is equal to the force the child exerted, for it to stay at rest (as Newton’s First Law stated).
I hope this helps! :)
M1u1 + m2u2 = m1v1 + m2v2
2 * 3 + 1 * 0 = 2 * 1 + 1 * v2
6 = 2 + v2
v2 = 6 - 2 = 4 m/s.