Imagine you are in a swimming pool 30m deep. Assuming you know that water is denser than air, you would know that the 30m of water above you will carry more weight, and press down on your body. Say you were in a swimming pool 60m deep, you would be sandwiched between 30m of water pressing down on you, and the upthrust created by the 30m of water below you.
In a building 30m up, the pressure will be regulated, as you are in a building. The floor will be strong enough to support the weight of the body, and the body will not recoil into itself.
Answer:
Part a)

Part b)

Explanation:
As we know that the see saw bar is massless so here torque due to two masses is given as

here we will have

now we will have inertia of two masses given as

now we have

now the angular acceleration is given as

so we have

Part b)
Now if the rod is not massles then we will have total inertia given as

so we will have

now the acceleration is given as


Answer:
(C) apparently written incorrectly - it should be 29.9 +- .3 K
(read 29.9 plus or minus .3 K)