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erica [24]
3 years ago
13

Astronomers can now report that active star formation was going on at a time when the universe was only 20% as old as it is toda

y. When astronomers make such a statement, how can they know what was happening inside galaxies way back then
Physics
1 answer:
disa [49]3 years ago
8 0

Answer:

First, as you may know, the light travels at a given velocity.

In vaccum, this velocity is c = 3x10^8 m/s.

And we know that:

distance = velocity*time

Now, if some object (like a star ) is really far away, the light that comes from that star may take years to reach the Earth.

This means that the images that the astronomers see today, actually happened years and years ago (So the night sky is like a picture of the "past" of the universe)

Also, for example, if an astronomer sees some particular thing, he can apply a model (a "simplification" of some phenomena that is used to simplify it an explain it) and with the model, the scientist can infer the information of the given thing some time before it was seen.

You might be interested in
Which best explains why magnets can push on or pull other magnets without touching them?
V125BC [204]
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. For example, the most well known form of magnetism is ferromagnetism such that some ferromagnetic materials produce their own persistent magnetic field. However, all materials are influenced to greater or lesser degree by the presence of a magnetic field. Some are attracted to a magnetic field (paramagnetism); others are repulsed by a magnetic field (diamagnetism); others have a much more complex relationship with an applied magnetic field. Substances that are negligibly affected by magnetic fields are known as non-magnetic substances. They include copper, aluminium, gases, and plastic. 

<span>The magnetic state (or phase) of a material depends on temperature (and other variables such as pressure and applied magnetic field) so that a material may exhibit more than one form of magnetism depending on its temperature, etc.
Or
 </span><span>If it's a multiple choice question this is the best answer: </span>
<span>A magnetic field surrounds each magnet, which affects other objects with magnetic fields
</span><span>hope this helpsss.
and can you help me as well with two questions if you dont mind


</span>
5 0
3 years ago
The distance between the centers of the wheels of a motorcycle is 146 cm. The center of mass ofthe motorcycle, including the rid
Vitek1552 [10]

Answer:

9.12267515924 m/s²

Explanation:

Here the moment created by the wheels and the moment created by the center of gravity will balance each other.

h = Height of the center of mass = 78.5 cm

d =  Distance from back wheel to the center of mass = \dfrac{146\times 10^{-2}}{2}\ m

g = Acceleration due to gravity = 9.81 m/s²

a = Horizontal acceleration

The equation is of the form

mgd=Fh\\\Rightarrow mgd=mah\\\Rightarrow a=\dfrac{gd}{h}\\\Rightarrow a=\dfrac{9.81\times \dfrac{146\times 10^{-2}}{2}}{78.5\times 10^{-2}}\\\Rightarrow a=9.12267515924\ m/s^2

The horizontal acceleration of the motorcycle that will make the front wheel rise off the ground is 9.12267515924 m/s²

8 0
3 years ago
2. A truck speeds up from a velocity of 6 m/s to 14 m/s in 4 seconds. What is the trucks acceleration? SHOW YOUR WORK
zavuch27 [327]

#2

As it is given here

initial speed is

v_i = 6 m/s

After 4 seconds the final speed is

v_f = 14 m/s

so here we can use the formula of acceleration using kinematics

a = \frac{v_f - v_i}{t}

a = \frac{14 - 6}{4}

a = 2 m/s^2

so here it will accelerate at 2 m/s^2 rate.

#3

As it is given here

initial it starts from rest

v_i = 0 m/s

After 2.5 seconds the final speed is

v_f = 15 m/s

so here we can use the formula of acceleration using kinematics

a = \frac{v_f - v_i}{t}

a = \frac{15 - 0}{2.5}

a = 6 m/s^2

so here it will accelerate at 6 m/s^2 rate.


#4

i think question is not correct as in first line it is saying about a bag of trash and then in next line it is asking for the position of Jumper and bridge.

7 0
3 years ago
A convex lens has a focal length of 16.5 cm. Where on the lens axis should an object be placed in order to get a virtual, enlarg
alexandr402 [8]

Answer:

Object should be placed at a distance, u = 7.8 cm

Given:

focal length of convex lens, F = 16.5 cm

magnification, m = 1.90

Solution:

Magnification of lens, m = -\frac{v}{u}

where

u = object distance

v = image distance

Now,

1.90 = \frac{v}{u}

v = - 1.90u

To calculate the object distance, u by lens maker formula given by:

\frac{1}{F} = \frac{1}{u}+ \frac{1}{v}

\frac{1}{16.5} = \frac{1}{u}+ \frac{1}{- 1.90u}

\frac{1}{16.5} = \frac{1.90 - 1}{1.90u}

\frac{1}{16.5} = \frac{ 0.90}{1.90u}

u = 7.8 cm

Object should be placed at a distance of 7.8 cm on the axis of the lens to get virtual and enlarged image.

6 0
4 years ago
Phân biệt các đặc điểm khác nhau giữa chất rắn, chất lỏng
vitfil [10]

Answer:

şen çal kapimi turkish drama

6 0
3 years ago
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