Answer:
Explanation:
We shall apply here Doppler's effect in optics . The formula is as follows

Δλ is change in wavelength , λ is original wavelength , v is velocity and c is velocity of light
Δλ = 685 - 590 = 95 nm
λ = 685
95 / 685 = v / 3 x 10⁸
v = .416 x 10⁸ m / s
= 4.16 x 10⁷ m /s
Answer:
-2.5m/s²
Explanation:
The acceleration of a body is giving by the rate of change of the body's velocity. It is given by
a = Δv / t ----------------(i)
Where;
a = acceleration (measured in m/s²)
Δv = change in velocity = final velocity - initial velocity (measure in m/s)
t = time taken for the change (measured in seconds(s))
From the question;
i. initial velocity = 5m/s
final velocity = 0 [since the body (ball) comes to rest]
Δv = 0 - 5 = -5m/s
ii. time taken = t = 2s
<em>Substitute these values into equation (i) as follows;</em>
a = (-5m/s) / (2s)
a = -2.5m/s²
Therefore, the acceleration of the ball is -2.5m/s²
NB: The negative sign shows that the ball was actually decelerating.
Answer:
The mass of the earth, 
Explanation:
It is given that,
Time taken by the moon to orbit the earth, 
Distance between moon and the earth,
We need to find the mass of the Earth using Kepler's third law of motion as :




So, the mass of the earth is
. Hence, this is the required solution.
I'm assuming we're applying the standard Integral form of the calculation of work. The solution is provided in the image.