Answer:
v = 31.32 [m/s]
Explanation:
To solve this problem we must use the principle of energy conservation, which tells us that potential energy is converted into kinetic energy or vice versa. The potential energy can be calculated by the product of mass by gravity by height.

where:
Epot = potential energy [J]
m = mass = 25 [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 50 [m]
Now replacing:
![E_{pot}=25*9.81*50\\E_{pot}= 12262.5[J]](https://tex.z-dn.net/?f=E_%7Bpot%7D%3D25%2A9.81%2A50%5C%5CE_%7Bpot%7D%3D%2012262.5%5BJ%5D)
When the rock falls the potential energy is converted into kinetic energy.

where:
Ek = kinetic energy [J]
v = velocity [m/s]
Now clearing v:
![v^{2} =\frac{E_{k}*2}{m}\\v=\sqrt{(2*12262)/25}\\v = 31.32 [m/s]](https://tex.z-dn.net/?f=v%5E%7B2%7D%20%3D%5Cfrac%7BE_%7Bk%7D%2A2%7D%7Bm%7D%5C%5Cv%3D%5Csqrt%7B%282%2A12262%29%2F25%7D%5C%5Cv%20%3D%2031.32%20%5Bm%2Fs%5D)
Answer:
a basis or standard for evaluation, assessment, or comparison; a criterion.
Explanation:
Definition of reference point. : something that is used to judge or understand something else The professor used the study as a reference point for evaluating and discussing other theories.
Answer:
375 ms
Explanation:
the frequency of metronome , f = 160 beats per minute
f = 160 /60 beats per sec
f = 2.67 beats /s
the period of a single beat , T = 1/f
T = 1/2.67 s
T = 0.375 s = 375 ms
the period of a single beat is 375 ms
Hi, I think the answer is False? I’m not fully sure bc I’m not considering air resistants. I’m sorry if this isn’t correct.
Answer:

Explanation:
According to the newton's second law of motion we can apply F=ma hear
Force = mass * acceleration
(assume the piano is moving left side )
←F = ma
