Answer: sliding
Explanation:
A snow skier slowing to a stop after skiing down a mountain is an example of sliding friction
<span>Calcium - alkali earth metals is the answer</span>
The correct answer for the question that is being presented above is this one: "Schmidt-Cassegrain focus." A focal arrangement that has a thin lens that the light passes through before traveling down the tube to the objective mirror is a Schmidt-Cassegrain focus.
Here are the following choices:
a. Cassegrain focus
b. Newtonian focus
c. Schmidt-Cassegrain focus
<span>d. Schmidt focus</span>
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