Answer:
a. Picture attached
b. V, X
c. 
d. It makes sense cosidering that a normal heart beat rate is between 60 and 100 beats per minute (bpm).
Explanation:
First we have to identify the unknown of this problem:

Considering the characteristics of the problem and that distance and velocity are specified, the acceleration is constant, for that reason we use the equations of uniformly accelerated motion as follows:

If we reorganize the equations, considering that
and
are zero because motion starts from rest , we have:

Finally, the analysis of the result leaves us to understand why the normal heart beat rate varies between 60 and 100 bpm.
The heat absorbed is calculated using the following equation:
Q = mCΔT
Q = heat absorbed
m = mass = 66 g
C = specific heat of iron = 0.449 J/g.°C
ΔT = temperature change = 20 - 7 =13°C
Therefore,
Q = 66*0.449*13 = 385.242 J
Answer: Increase in wave frequency
Explanation:
When we talk about acoustics we are dealing with sound waves, and one of their main components along with the velocity and wavelength is the <u>frequency.</u>
In this sense, the frequency of any wave refers to how fast (or slow) a wave oscillates. For example, in the especific case of sound waves when the oscillation is faster, the frequency is higher and the pitch gets higher as well.
Answer:
The work input during this process is -742 kJ
Explanation:
Given;
Initial temperature of nitrogen T₁ = 250 K
final temperature of nitrogen T₂ = 450 K
mass of nitrogen, m = 5 kg

The work input during the process is calculated as;

where;
R is gas constant = 0.2968 kJ/kgK
substitute given values in above equation.

Therefore, the work input during this process is -742 kJ