Answer:
The compression in the spring is 5.88 meters.
Explanation:
Given that,
Mass of the car, m = 39000 kg
Height of the car, h = 19 m
Spring constant of the spring, 
We need to find the compression in the spring in stopping the ore car. It can be done by balancing loss in gravitational potential energy and the increase in elastic energy. So,

x is the compression in spring

So, the compression in the spring is 5.88 meters.
Answer:
4.7 x 10³ rad / s
Explanation:
During the time light goes and comes back , one slot is replaced by next slot while rotating before the light source
Time taken by light to travel a distance of 2 x 500 m is
= (2 x 500) / 3 x 10⁸
= 3.333 x 10⁻⁶ s .
In this time period, two consecutive slots come before the source of light one after another by rotation. There are 400 slots so time taken to make one rotation
= 3.333 x 10⁻⁶ x 400
= 13.33 x 10⁻⁴ s
This is the time period so
T = 13.33 X 10⁻⁴
Angular speed
= 2π / T
= 
4.7 x 10³ rad / s
Answer:
This is due to a relative decrease in atmospheric pressure in high places.
Explanation:
Given that atmospheric pressure decreases at the higher point or ground, this reduced atmospheric pressure, however, will be unable to contain the Mercury in the barometer tube.
Therefore, at the top of the mountain where the air pressure is low, the barometer reading ultimately goes down.
Hence, the level of mercury falls in a barometer while taking it to a mountain "due to a relative decrease in atmospheric pressure in high places."
Answer:
When something happens, energy is changed from one form into another.
Explanation:
correct me if I'm wrong