I just got this question not to long ago but to answer your question the primary function of the respiratory system is to exchange oxygen<span> and carbon dioxide. Inhaled </span>oxygen enters the lungs<span> and reaches the alveoli. </span>Oxygen<span> passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.</span>
<u>Answer:</u>
The acceleration of the plane and the time required to reach this speed is (a)= 7.5
and time(t) = 20 seconds
<u>Explanation:
</u>
Given data Initial velocity
= 0
Final velocity (
) = 150 m/second
Distance (d) = 1500 m
We have the formula, 
which gives
= 0+2a(1500)
22500 = 3000 a
acceleration (a) = 7.5 

150 = 7.5 t
t= 150/7.5 = 20
t = 20 seconds.
The person walking down the sidewalk follows the newton's third law of motion.
Explanation:
- A person is able to walk down the sidewalk by using the reaction forces from the ground.
- In simple term, feet pushes the ground and the reaction forces makes the feet able to walk.
- Another important force included in the walking mechanism is friction. With out friction one cannot walk down the sidewalks.
- Hence the forces involved in the walking of a person down the sidewalk are:
- Friction force
- Action and reaction force between ground and person's feet.
Answer:
29.4 N/m
0.1
Explanation:
a) From the restoring Force we know that :
F_r = —k*x
the gravitational force :
F_g=mg
Where:
F_r is the restoring force .
F_g is the gravitational force
g is the acceleration of gravity
k is the constant force
xi , x2 are the displacement made by the two masses.
Givens:
<em>m1 = 1.29 kg</em>
<em>m2 = 0.3 kg </em>
<em>x1 = -0.75 m </em>
<em>x2 = -0.2 m </em>
<em>g = 9.8 m/s^2 </em>
Plugging known information to get :
F_r =F_g
-k*x1 + k*x2=m1*g-m2*g
k=29.4 N/m
b) To get the unloaded length 1:
l=x1-(F_1/k)
Givens:
m1 = 1.95kg , x1 = —0.75m
Plugging known infromation to get :
l= x1 — (F_1/k)
= 0.1
Explanation:
Watts are defined as 1 Watt = 1 Joule per second (1W = 1 J/s)
which means that 1 kW = 1000 J/s. A Watt is the amount of energy (in Joules) that an electrical device (such as a light) is burning per second that it's running.