Answer:

Explanation:
Given:
mass of person, 
mass of merry go-round, 
radius of merry go-round, 
velocity of the person running, 
<u>We consider merry go-round as a ring:</u>
Now the moment of inertial of the ring is given as,



<u>Moment of inertia of the person considering as a point mass:</u>



<u>Now according to the conservation of angular momentum:</u>

where:
angular velocity of the merry-go-round
angular velocity of the person running



The difference between the frequencies of the piano key and the tuning fork gives the frequency of the beats.
When the tuning fork is 405 Hz, and no beats are heard, then the piano key is also 405 Hz.
When the piano key is 405 Hz and the tuning fork is 402 Hz, then 405 - 402 = 3 beats are heard.
The piano key is 405 Hz.
<span>To answer this question with specific values, you would need a phase diagram for the substance in question. In more general terms, the pressure needs to be lower than the pressure of the triple point, the substance must be present in its solid state, and the temperature must rise high enough to produce a gas.</span>
(A) We can solve the problem by using Ohm's law, which states:

where
V is the potential difference across the electrical device
I is the current through the device
R is its resistance
For the heater coil in the problem, we know

and

, therefore we can rearrange Ohm's law to find the current through the device:

(B) The resistance of a conductive wire depends on three factors. In fact, it is given by:

where

is the resistivity of the material of the wire
L is the length of the wire
A is the cross-sectional area of the wire
Basically, we see that the longer the wire, the larger its resistance; and the larger the section of the wire, the smaller its resistance.
When we breathe in air at sea level, the atmospheric pressure of about 14.7 pounds per square inch (1.04 kg. per cm.2) causes oxygen to easily pass through selectively permeable lung membranes into the blood. At high altitudes, the lower air pressure makes it more difficult for oxygen to enter our vascular systems.
hope this helps :)