Mountains, tops of buildings, and high-flying aircraft are all part of Earth's atmosphere, no matter how high they are. On the other hand, space doesn't belong to our atmosphere, it is outside of it. Having this in mind, the best location to place a telescope used to observe x-rays from stars is in space.
'A' is correct. B, C, and D are false statements.
Answer: when you increase or decrease your speed.
Explanation:
Moving a skate at rest, you need to apply force in order to cause acceleration.
F = ma Where
F = force applied
m = mass of the skate
a = acceleration
The initial velocity u will be equal to zero and the skate will acceleration to a certain velocity.
as you skate down your neighborhood sidewalk, you will accelerate when you increase your speed. Because
Acceleration is the rate of change of velocity. That is,
Acceleration = change in velocity/ time.
And also, you will decelerate when you reduce the speed or velocity down your neighborhood sidewalk.