Answer:

Explanation:
Given that
d= 1.5 in ( 1 in = 0.0254 m)
d= 0.0381 m
P= 75 hp ( 1 hp = 745.7 W)
P= 55927.5 W
N= 1800 rpm
We know that power P is given as

T=Torque
N=Speed

T=296.85 N.m
The maximum shear stress is given as



We know that 1 MPa =0.145 ksi

For this case we have that by definition, the momentum is given by:

Where,
- <em>m: mass
</em>
- <em>v: speed
</em>
Therefore, replacing values we have:

From here, we clear the value of the speed:

Answer:
The magnitude of velocity is:

Well, the acceleration is the difference of speeds divided by the time period.

.
One rev/s is

, so our final result is

.
<span>This is because Helium
has two valence electrons compared to Hydrogen which has only one. Helium has
more energy levels for an electron to jump thus more spectral lines to occur.
The spectral lines relating to each change of energy level would be more
grouped together and hence the greater chance of them falling in the visible
range.</span>
Answer B is the correct pair.