The full question is found in the image attached
Answer:
Densities
Explanation:
When we talk about density, one of the things that come to our mind is actually how heavy something is.
If i have substances that possess different densities, i will notice that i can not really mix them because they will separate and the heavier substance will be at the bottom while the lighter substance will be at the top.
Hence the two substances separated due to difference in density.
Displacement = 0, assuming that he runs back to original position
Average velocity is displacement/ time, since displacement =0, velocity is also 0
Answer:

Explanation:
Given that,
Radius of a spherical shell, r = 0.7 m
Torque acting on the shell, 
Angular acceleration of the shell, 
We need to find the rotational inertia of the shell about the axis of rotation. The relation between the torque and the angular acceleration is given by :

I is the rotational inertia of the shell

So, the rotational inertia of the shell is
.