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3 years ago

How can the sun have both a brightness of -26.73 and 4.83? Explain what these numbers mean.

1 answer:

3 0

The Sun has an "absolute magnitude" of 4.83 and an "apparent" magnitude of -26.8. (Which is the difference between the numbers). Scientists use what is know as "Absolute" Magnitude to help them understand and compute how bright a star really is. The "absolute" magnitude of an object, such as a star, equals how bright that object would look if it were 10 parsecs, or 32.6 light years away from the Earth.

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If we have less power, we most likely have

katrin [286]

the same amount of work being done over a longer period of time.

3 0

2 years ago

Read 2 more answers

A small block of mass 20.0 grams is moving to the right on a horizontal frictionless surface with a speed of 0.68 m/s. The block

Usimov [2.4K]

Answer:

a) $v'=-0.227\ m.s^{-1}$

b) $v=1.36\ m.s^{-1}$

Explanation:

Given:

mass of the lighter block, $m'=0.02\kg$

velocity of the lighter block, $u'=0.68\ m.s^{-1}$

mass of the heavier block, $m=0.04\ kg$

velocity of the heavier block, $u=0\ m.s^{-1}$

Using conservation of linear momentum:

$m'.u'+m.u=m'.v'+m.v$

where:

$v'=$ final velocity of the lighter block

$v=$ final velocity of the heavier block

$m'.u'=m'.v'+m.v$

$m'(u'-v')=m.v$ ........................(1)

Since kinetic energy is conserved in elastic collision:

$\frac{1}{2}m'.u'^2=\frac{1}{2}m'.v'^2+\frac{1}{2}m.v^2$

$m'(u'^2-v'^2)=m.v^2$

$m'(u'-v')(u'+v')= m.v^2$

divide the above equation by eq. (1)

$v=u'+v'$ .............................(2)

now we substitute the value of v from eq. (2) in eq. (1)

$m'(u'-v')=m(u'+v')$

$\frac{m'+m}{m'-m} =\frac{u'}{v'}$

$\frac{0.02+0.04}{0.02-0.04} =\frac{0.68}{v'}$

$v'=-0.227\ m.s^{-1}$ (negative sign denotes that the direction is towards left)

now we substitute the value of v' from eq. (2) in eq. (1)

$m'(u'-v+u')=m.v$

$2m'.u'=(m-m')v$

$2\times 0.02\times 0.68=(0.04-0.02)\times v$

$v=1.36\ m.s^{-1}$

6 0

3 years ago

A 1.50 3 103 - kg car starts from rest and accelerates uniformly to 18.0 m/s in 12.0 s. Assume that air resistance remains const

nexus9112 [7]

Answer:

Explanation:

let force exerted by engine be F.Net force =( F-400)N, applying newton law

F-400 = 1.5 x 10³x18 =27000 ,

F = 27400 N.

velocity after 12 s = 0 + 18 x 12 = 216 m/s

Average velocity = (0 + 216 )/2 = 108 m/s

Average power = force x average velocity = 27400 x 108 = 29.6 10⁵ W .⁶

b) At 12 s , velocity = 216 m/s

Instantaneous power = velocity x force = 216 x 27400 = 59.2 x 10⁶ W.

8 0

3 years ago

Read 2 more answers

The ability of your joints and muscles to move in their full range of motion is called

Studentka2010 [4]

Answer:

Dynamic flexibility

Explanation:

Dynamic flexibility can be generally defined as the ability of the body muscles and joints to move in full range of motion. High flexibility in these joints and muscles leads to the decreasing pain and injury in different parts of the body.

Proper warm up exercises are needed to be carried out that involves both the combination of controlling movements and stretching of the body, and this directly enhances the dynamic flexibility of the body.

The athletes and sports persons possesses a good dynamic flexibility of their body as they carry our different types of body exercises.

6 0

2 years ago

An electric motor with a 1200 hp output drives a machine with an efficiency of 60%. What is the energy output of the machine per

kirill [66]

Answer:

536,904 J/s

Explanation:

The energy output from motor is the input energy in the machine.

We know that efficiency is percentage energy ouput to energy input, and expressed as

$n=\frac {E_o}{E_i}$

Where n and E represent efficiency and energy respectively, subscripts o and i represent output and input respectively. Since for the machine we have the input energy then the output will be the product of efficiency and input energy

Energy output=0.6*1200 hp=720 hp

Converting hp to J/s we multiply by 745.7

Energy is 720*745.7=536,904 J/s

4 0

3 years ago