This shifts the star’s spectral lines toward the blue end of the spectrum. If the star is moving away from us, it’s waves are effectively stretched out when they reach earth, increasing their wavelength. This shifts the star’s spectral lines toward the red end of the spectrum.
Answer:
The minimum speed of the box bottom of the incline so that it will reach the skier is 8.19 m/s.
Explanation:
It is given that,
Mass of the box, m = 2.2 kg
The box is inclined at an angle of 30 degrees
Vertical distance, d = 3.1 m
The coefficient of friction, 
Using the work energy theorem, the loss of kinetic energy is equal to the sum of gain in potential energy and the work done against friction.


W is the work done by the friction.







v = 8.19 m/s
So, the speed of the box is 8.19 m/s. Hence, this is the required solution.
By 2nd Newton's Law.
F =m*g
For 1st body
Let it's force be x
thus,
x = m*g --------- eqn 1
For mass 2,
F = 4m*g
g = F/4m -------- eqn 2
For the first body's force interms of second body substitute eqn 2 into 1
x = m*(F/4m)
x = <u>m</u><u>*</u><u>F</u>
4m
x = F/4
Therefore, the force on mass m interms of F is
F/4.