In order to answer this question, I realized that I needed to know the index
of refraction for ruby, so I went and looked it up. It's 1.762 to 1.770 .
I started trying to remember how to use this number and the critical angle
to find the index of refraction of the other medium. That's when I saw the
absurd unit "degrees celsius" for the critical angle, and I got discouraged.
But I perked up very quickly, when I realized that I'm still on the "index of
refraction" list, and while I'm there, I might as well just go ahead and
look up ethyl alcohol too.
It's 1.36 .
Answer:
B. blocks 2 & 3.
Explanation:
Block 1 has equal & opposite forces acting on it.
Block 2 has 5N on one side, 3N on the other. It will move in the direction the 5N of force is pushing.
Block 3 has no opposing force.
Answer:
3.At equilibrium, its instantaneous velocity is at maximum
Explanation:
The motion of a mass on the end of a spring is a simple harmonic motion. In a simple harmonic motion, the total mechanical energy of the system is constant, and it is sum of the elastic potential energy (U) and the kinetic energy of the mass (K):

where
k is the spring constant
x is the displacement of the spring from equilibrium
m is the mass
v is the speed
As we see from the formula, since the total energy E is constant, when the displacement (x) increases, the speed (v) increases, and viceversa. Therefore, when the mass is at its equilibrium position (which corresponds to x=0), the velocity of the mass will be maximum.
Answer:
horrible, but how about you?
Explanation: