Answer:
Explanation:
Check attachment for solution
Given that, .
The initial gas pressure is
P1 = 3 MPa
The initial gas temperature
T1 = 300°C
The final gas pressure is
P2 = 80 KPa
Which are of two choices
1. Air with an isentropic expansion of 90% efficiency
2. Neon with an isentropic expansion of 80% efficiency
We want to know which will produce more work
Answer:
(a)
(b)
1120 N
Explanation:
Change in velocity, is given by subtracting the initial velocity from the final velocity and expressed as
Where v represent the velocity and subscripts f and i represent final and initial respectively. Since the ball finally comes to rest, its final velocity is zero. Substituting 0 for final velocity and the given figure of 8 m/s for initial velocity then the change in velocity is given by
To find then we substitute 7 kg for m and -8 m/s for
therefore
(b)
The impact force, F is given as the product of mass and acceleration. Here, acceleration is given by dividing the change in velocity by time ie
Substituting t with 0.05 s then
Since F=ma then substituting m with 7 Kg we get that F=7*-160=-1120 N
Therefore, the impact force is equivalent to 1120 N
Answer:
b) Betelgeuse would be times brighter than Sirius
c) Since Betelgeuse brightness from Earth compared to the Sun is the statement saying that it would be like a second Sun is incorrect
Explanation:
The start brightness is related to it luminosity thought the following equation:
(1)
where is the brightness,
is the star luminosity and
, the distance from the star to the point where the brightness is calculated (measured). Thus:
b) and
where
is the Sun luminosity (
) but we don't need to know this value for solving the problem.
is light years.
Finding the ratio between the two brightness we get:
c) we can do the same as in b) but we need to know the distance from the Sun to the Earth, which is . Then
Notice that since the star luminosities are given with respect to the Sun luminosity we don't need to use any value a simple states the Sun luminosity as the unit, i.e 1. From this result, it is clear that when Betelgeuse explodes it won't be like having a second Sun, it brightness will be 5 orders of magnitude smaller that our Sun brightness.
Answer:
New Resistance = 0.5556 ohm
Explanation:
Resistance = resistivity * length /area
Here since resistivity and length are constant, we only need to see how the resistance increases or decreases with change in area.
New Area = pi * (3*D)^2 / 4
Old Area = pi * D^2 / 4
The ratio of new area / old area is :
Since area increases 9 times, and it is inversely proportional to resistance:
Resistance decreases by 9 times.
So, old resistance = Voltage / Current = 10 / 2 = 5 ohm
New Resistance = 5 / 9 = 0.5556 ohm (decreases by 9 times)