The height difference is found by

Then the change in potential energy is
Answer:
Speed of another player, v₂ = 1.47 m/s
Explanation:
It is given that,
Mass of football player, m₁ = 88 kg
Speed of player, v₁ = 2 m/s
Mass of player of opposing team, m₂ = 120 kg
The players stick together and are at rest after the collision. It shows an example of inelastic collision. Using the conservation of linear momentum as :

V is the final velocity after collision. Here, V = 0 as both players comes to rest after collision.



So, the speed of another player is 1.47 m/s. Hence, this is the required solution.
Answer:
1). 
2). Toward us
3). 
4). Toward us
5). 
6). Away from us
7). 
8). Away from us
Explanation:
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when it is moving away from the observer (that is known as the Doppler effect).
The wavelength at rest is 121.6 nm (
)

Then, for this particular case it is gotten:
Star 1: 
Star 2:
Star 3:
Star 4:
Star 1:
Toward us
Star 2:
Toward us
Star 3:

Away from us
Star 4:

Away from us
Due to that shift the velocity of the star can be determine by means of Doppler velocity.
(1)
Where
is the wavelength shift,
is the wavelength at rest, v is the velocity of the source and c is the speed of light.
(2)
<em>Case for star 1
:</em>
<em></em>
Notice that the negative velocity means that is approaching to the observer.
<em>Case for star 2
:</em>
<em>Case for star 3
:</em>
<em>Case for star 4
:</em>
Answer:
To obtain the power, we first need to find the work made by the force.
1) To calculate the work, we need the next equation:

So the force is given by the problem so our mission is to find 'dx' in terms of 't'
2) we know that:

So we have:

Then:

3) Finally, we replace everything:

After some calculation, we have as a result that the work is:
161.9638 J.
4) To calculate the power we need the next equation:

So
P = 161.9638/4.7 = 34.46 W