If the rock is just sitting there and you want to SLIDE it, then you have to push it with a force of at least
(251 kg) x (9.8 m/s²) x (μ) =
(2,459 Newtons) x (the coefficient of static friction on that surface)
Answer:
The second material's index of refraction is 1.17.
Explanation:
Given that,
Refractive index of the material, n = 1.29
Critical angle is 65.9 degrees.
We need to find the second material's index of refraction. We know that at critical angle of incidence, angle of refraction is equal to 90 degrees. Using Snell's law as:

So, the second material's index of refraction is 1.17.
A control is B, standard for comparison. This is used to compare for example plants and using different fertilizers and then have one with no fertilizer. Controls are basically just a base to the entire experiment
I hope this helps you!:)

where:
F - force
m - mass
a - acceleration
We transform this formula to get a:
