Answer:
k = 40 N/m
Explanation:
A spring's energy is given:

U is the energy in the spring, k is the spring constant and x is the spring displacement.
We are told that the spring stores 5J of energy, therefore, U = 5J. We are also told that the spring is compressed by 0.5m, so the spring x = 0.5m

k = 40 N/m
Hope this helps!
Answer:
Explanation:add them then divide them by 100 I think
When light travels from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle of incidence above which light is reflected only (no refraction occurs), and the value of this critical angle is given by

where n2 is the refractive index of the second medium and n1 is the refractive index of the first medium.
In this problem, the first medium is the glass (

), while the second medium is oil (

), therefore the critical angle is given by
There is reflection if that might work
Answer:
The most accurate and precise method to measure the thickness of a coin would be by a micrometer screw guage.