#1
As we know that

now plug in all data into this


now from the formula of strain




#2
As we know that
pressure * area = Force
here we know that


now force is given as

#3
As we know that density of water will vary with the height as given below

here we know that


now density is given as


#4
as we know that pressure changes with depth as per following equation

here we know that

now we will have



here we will have

so it is 20.1 m below the surface
#5
Here net buoyancy force due to water and oil will balance the weight of the block
so here we will have




so it is 3.48 cm below the interface
Explanation:
If a metal rod of length L moves with velocity v is moving perpendicular to its length, in a magnetic field B, the induced emf is given by :

The electric field in the conductor is given by :

It is clear that the electric field is independent of the length of the rod. If the length of the rod is doubled, the electric field in the rod remains the same.
I think metal, steel and copper.
Speed = distance / time.
Speed of him leaving the nest:
S = 100 / 20sec
5 m/s.
Catching the snake:
S2 = 50 / 5sec
10 m/s.
Average of 5& 10 = 7.5
7.5 m/s has to be the answer.
The starting point for measuring motion is called : The Reference Point.