Answer:
rest and motion are the relative terms because they depend on the observer's frame of reference. So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body
Explanation:
Answer:
42.11 years old
Explanation:
Given that:
In 2000, a 20-year-old astronaut left Earth to explore the galaxy; her spaceship travels at 2.5 x 10^8 m/s. She returns in 2040
To find her age we use:

Δtm is time interval for the observer stationary relative to the sequence of
events = 2040 - 2000 = 40 years
Δts is is the time interval for an observer moving with a speed v relative to the sequence of event
v = velocity = 2.5 x 10^8 m/s
c = speed of light = 3 x 10^8 m/s

Here age in 2000 is 20 year, therefore when she appear she would be 20 year + 22.11 year = 42.11 years old
Answer:
We only see one side of the moon due to the synchronous rotations and the earth rotation ration is approximately 27 days
Explanation:
Mass x SH x °C (or K) ΔT
= 75g x 0.45J/g/K x 6.0 ΔT
= 202.5 Joules of heat absorbed.
(202.5J / 4.184J/cal = 48.4 calories).
I guess that is the answer