Answer:
8 Hz
Explanation:
Given that
Standing wave at one end is 24 Hz
Standing wave at the other end is 32 Hz.
Then the frequency of the standing wave mode of a string having a length, l, is usually given as
f(m) = m(v/2L), where in this case, m could be 1. 2. 3. 4 etc
Also, another formula is given as
f(m) = m.f(1), where f(1) is the fundamental frequency..
Thus, we could say that
f(m+1) - f(m) = (m + 1).f(1) - m.f(1) = f(1)
And as such,
f(1) = 32 - 24
f(1) = 8 Hz
Then, the fundamental frequency needed is 8 Hz
As per the question the mass of the boy is 50 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Hence the weight of the boy 
[m is the mass of the body]
we have m = 50 kg.
Hence w = 50 kg ×9.8 m/s^2
=490 N kg m/s^2
= 490 N
Here newton [N] is the unit of force.
The answer is C. Sulfuric Acid is dangerous to living organism
Direct contact with your skin and it will cause Chemical Burns , Direct contact with your eyes and it could cause a permanent Blindness.
This chemical also suck the water out of everything, so you can guess what will happen if it get into your body.
The law of universal gravitation says that one object attracts every other object using a proportional force to the mass of the object.
