Our Sun is a G2V star with absolute magnitude 4.8. Suppose that a star of spectral type G2V is observed to have apparent magnitu
1 answer:
Answer:
Option D
The star is at a distance of 100 parsecs.
Explanation:
The distance can be determined by means of the distance modulus:
(1)
Where M is the absolute magnitude, m is the apparent magnitude and d is the distance in units of parsec.
Therefore, d can be isolated from equation 1
Then, Applying logarithmic properties it is gotten:
(2)
The absolute magnitude is the intrinsic brightness of a star, while the apparent magnitude is the apparent brightness that a star will appear to have as is seen from the Earth.
Since both have the same spectral type is absolute magnitude will be the same.
Finally, equation 2 can be used:
Hence, the star is at a distance of 100 parsecs.
<em>Key term:</em>
Parsec: Parallax of arc seconds
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Answer:
The angular speed is 0.13 rev/s
Explanation:
From the formula
Where is the torque
is the moment of inertia
is the angular acceleration
But, the angular acceleration is given by
Where is the angular speed
and is time
Then, we can write that
Hence,
Now, to determine the angular speed, we first determine the Torque and the moment of inertia
.
Here, The torque is given by,
Where r is the radius
and F is the force
From the question
r = 3.00 m
F = 195 N
∴
Nm
For the moment of inertia,
The moment of inertia of the solid disk is given by
Where M is the mass and
R is the radius
∴
kgm²
From the question, time t = 2.05 s.
Putting the values into the equation,
rad/s
Now, we will convert from rad/s to rev/s. To do that, we will divide our answer by 2π
0.82 rad/s = 0.82/2π rev/s
= 0.13 rev/s
Hence, the angular speed is 0.13 rev/s,