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4 years ago

The apparent visual magnitude of a star is 7.3. This tells us that the star is _______.

Physics

1 answer:

fredd [130]4 years ago

8 0

Answer:

Option (B)

Explanation:

In the field of astronomy, the magnitude scale of star is usually defined as a logarithmic scale that measures the brightness of the star, and this directly the relative distance from the earth. This magnitude value is dependent on the two main factors, namely the its brightness and the distance from a fixed point.

The given visual magnitude of a star is 7.3, and is comparatively very less brighter. This shows a relatively very large distance from the earth and due to this large distance and low luminousity, this star is not visible to our naked eye.

Thus, the correct answer is option (B).

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The center of a moon of mass m is a distance D from the center of a planet of mass M. At some distance x from the center of the

nataly862011 [7]

Answer with Explanation:

Let rest mass $m_0$ at point P at distance x from center of the planet, along a line connecting the centers of planet and the moon.

Mass of moon=m

Distance between the center of moon and center of planet=D

Mass of planet=M

We are given that net force on an object will be zero

a.We have to derive an expression for x in terms of m, M and D.

We know that gravitational force= $\frac{GmM}{r^2}$

Distance of P from moon=D-x

$F_m$ =Force applied on rest mass due to m

$F_m$ =Force on rest mass due to mas M

$F_M=F_m$ because net force is equal to 0.

$F_m=F_M$

$\frac{Gm_0m}{(D-x)^2}=\frac{Gm_0M}{x^2}$

$\frac{m}{(D-x)^2}=\frac{M}{x^2}$

$\frac{x^2}{(D-x)^2}=\frac{M}{m}$

$\frac{x}{D-x}=\sqrt{\frac{M}{m}}$

Let $R=\sqrt{\frac{M}{m}}$

Then, $\frac{x}{D-x}=R$

$x=DR-xR$

$x+xR=DR$

$x(1+R)=DR$

$x=\frac{DR}{1+R}$

b.We have to find the ratio R of the mass of the mass of the planet to the mass of the moon when x= $\frac{2}{3}D$

Net force is zero

$F_m=F_M$

$\frac{Gm_0m}{(D-\frac{2}{3}D)^2}=\frac{Gm_0M}{\frac{4}{9}D^2}$

$\frac{m}{\frac{D^2}{9}}=\frac{9M}{4D^2}$

$\frac{M}{m}=4$

Hence, the ratio R of the mass of the planet to the mass of the moon=4:1

8 0

4 years ago

Electromagnets are created by (2 points)

KIM [24]

I believe the correct answer is B

5 0

3 years ago

Help?

ankoles [38]

center, power forward, small forward, point guard and shooting guard

1896

the University of Chicago and the University of Iowa

James Naismith was a physical education teacher

Sprinfield College

Upon the request of his boss, Naismith was tasked to create an indoor sports game to help athletes keep in shape as they endured the cold New England winters. Naismith's boss also stipulated that this new game should be "fair for all players and not too rough."

I just looked it up hope this helps tho.

8 0

3 years ago

How does the theory of plate tectonics explain these similarities of location?

Nookie1986 [14]

he theory states that Earth's outermost layer, the lithosphere, is broken into 7 large, rigid pieces called plates: the African, North American, South American, Eurasian, Australian, Antarctic, and Pacific plates. Several minor plates also exist, including the Arabian, Nazca, and Philippines plates. The plates are all moving in different directions and at different speeds

7 0

3 years ago

A crate is pulled 7 m across a smooth surface. The tension in the rope pulling the crate is 40 N. If the work on the crate is 24

Marina CMI [18]

Answer:

61.9°

Explanation:

The formula for calculating the workdone is expressed as

Workdone = Fdsin theta

F is the force applied on the crate

d is the distance covered

theta is the angle that the rope makes with the horizontal

Given

F = 40N

d = 7m

Workdone = 247J

Substituting into the formula:

247 = 40(7)sin theta

247 = 280sin theta

sin theta = 247/280

sin theta = 0.88214

theta = arcsin(0.88214)

theta = 61.9°

Hence the angle that the rope makes with the horizontal is 61.9°

5 0

3 years ago