3.33 seconds.
<u>Explanation:</u>
We can find the speed of the body using the formula,
Speed = Distance traveled in meters / time taken in seconds
= 450 m / 30 seconds
= 15 m/s
So per second the distance traveled by the body is 15 m.
So time needed to travel 50 m can be found as,
time = distance/speed
= 50 m / 15 m /s
= 3.33 s
At the present time, the only way we know of that light can get shifted
toward the blue end of the spectrum is the Doppler effect ... wavelengths
appear shorter than they should be when the source is moving toward us.
IF that's true in the case of the Andromeda galaxy, it means the galaxy is
moving toward us.
We use the same reasoning to conclude that all the galaxies whose light is red-shifted are moving away from us. That includes the vast majority of all galaxies that we can see, and it strongly supports the theory of the big bang
and the expanding universe.
If somebody ever comes along and discovers a DIFFERENT way that light
can get shifted to new, longer or shorter wavelengths, then pretty much all
of modern Cosmology will be out the window. There's a lot riding on the
Doppler effect !
When we jump from the truck and accelerate towards the earth surface, the earth also accelerates towards us but it's acceleration is very negligible.
To find the answer, we need to know about the acceleration of earth due to the gravitational attraction.
<h3>What's the gravitational force between the earth and a person?</h3>
- Gravitational attraction force is GMm/r² between the earth and a person.
- M= mass of the earth
m= mass of the person
r= separation between them.
<h3>What's the acceleration of the earth towards the person when he jumps from a truck?</h3>
- According to Newton's second law, Force = M×acceleration
- Acceleration= Force / M
- Here, Force = GMm/r²,
so acceleration of earth= Gm/r²
- As this acceleration is very small, so we can't notice it.
Thus, we can conclude that the earth also accelerates towards us.
Learn more about the gravitational force here:
brainly.com/question/72250
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The acceleration due to gravity is given as:
g = GM/r²
<h3>
Derivation of gravitational acceleration:</h3>
According to Newton's second law of motion,
F = ma
where,
F = force
m = mass
a = acceleration
According to Newton's law of gravity,
F<em>g </em>= GMm/(r + h)²
F<em>g = </em>gravitational force
From Newton's second law of motion,
F<em>g </em>= ma
a = F<em>g</em>/m
We can refer to "a" as "g"
a = g = GMm/(m)(r + h)²
g = GM/(r + h)²
When the object is on or close to the surface, the value of g is constant and height has no considerable impact. Hence, it can be written as,
g = GM/r²
Learn more about gravitational acceleration here:
brainly.com/question/2142879
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