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alexgriva [62]
3 years ago
10

From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanome

ters (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm.
What can we conclude?

a) The star is moving toward us.
b) The star is moving away from us.
c) The star is getting hotter.
d) The star is getting colder.
e) The "star" actually is a planet.
Physics
1 answer:
lina2011 [118]3 years ago
7 0

Answer:

b) The star is moving away from us.

Explanation:

If an object moves toward us, the light waves it emits are compressed - the wavelength of the light will be shorter, making the light bluer. On the other hand, if an object moves away from us, the light waves are stretched, making it redder. If from laboratory measurements we know that a specific hydrogen spectral line appears at the wavelength of 121.6 nanometers (nm) and the spectrum of a particular star shows the same hydrogen line appearing at the wavelength of 121.8 nm, we can conclude that the star is moving away from npos, since the wavelength related to that star is more expanded.

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A wrench is used to tighten a spark plug. If the wrench handle is 0.20m and a force of 20N is applied, what is the torque applie
Zanzabum

Torque [Nm] = Force [N] x Force arm [m]

C=F*b=20*0.20=4 Nm

The correct answer is C


4 0
2 years ago
Which equation represents the law of conservation of energy in a closed system?
Irina-Kira [14]

Answer:

KE + PE = KE + PE

Explanation:

In a closed system, the mechanical energy of the system is constant.

Mechanical energy is given by the sum of kinetic energy and potential energy; mathematically:

U = KE + PE

where

KE is the kinetic energy

PE is the potential energy

This means that if we consider two situations, one at the beginning and one at the end, the value of U will not change if the system is closed; this means that the sum KE + PE will remain the same, so we can write:

KE + PE = KE + PE

7 0
3 years ago
Read 2 more answers
Chemical properties of an acid include...
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and C. corrosive, increases the concentration of hydrogen ions when added to water, forms hydrogen gas when it comes in contact with a metal, and formssalt and water when added to a base.

5 0
2 years ago
A world-class sprinter can burst out of the blocks to essentially top speed (of about 11.5 m/s) in the first 15.0 m of the race.
wolverine [178]
Given:
u = 0, initial speed (sprinter starts from rest)
v = 11.5 m/s, final speed
s = 15 m, distance traveled to attain final speed.

Let
a =  average acceleration,
t = time taken to attain final speed.

Then
v² = u² + 2as
or
(11.5 m/s)² = 2*(a m/s²)*(15 m)
a = 11.5²/(2*15) = 4.408 m/s²

Also
v = u +a t
or
(11.5 m/s) = (4.408 m/s²)*(t s)
t = 11.5/4.408 = 2.609 s

Answer:
The average acceleration is 4.41 m/s² (nearest hundredth).
The time required is 2.61 s (nearest hundredth).
8 0
3 years ago
A bobsled team accelerates the sled to go to 150 m/s in 3 seconds from rest.(a)What is the
Sergeeva-Olga [200]

Answer:

Explanation:

From the equation of Newton's laws of motion

v = u + at where v is final velocity , u is initial velocity and t is time.

150 = 0 + a x 3

a = 50 m / s ²

s = ut + 1/2 at²  ; s is distance travelled

s = 50 x 3 + .5 x 50 x 3²

= 150 + 225

= 375 m .

7 0
2 years ago
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