Good afternoon!
We can see that

The index of refraction can be calculated as:

As we noted,

, and therefore:

Beccause n = c/v, we have:
n > 1B - Is more than 1.
Answer:
The spring constant is 60,000 N
The total work done on it during the compression is 3 J
Explanation:
Given;
weight of the girl, W = 600 N
compression of the spring, x = 1 cm = 0.01 m
To determine the spring constant, we apply hook's law;
F = kx
where;
F is applied force or weight on the spring
k is the spring constant
x is the compression of the spring
k = F / x
k = 600 / 0.01
k = 60,000 N
The total work done on the spring = elastic potential energy of the spring, U;
U = ¹/₂kx²
U = ¹/₂(60000)(0.01)²
U = 3 J
Thus, the total work done on it during the compression is 3 J
So we know coefficient of f times normal force is friction. So do 100= .25 times x. Now solve for x. You get 400. So 400 is the normal force. And we know normal force equals weight in these types of problems so the answer is 400
Look, according to newton’s law of the conservation of mass power, the principle behind the electric generator would be when a conductor is moved in a magnetic field than the current is moved buh the conductor