Answer:
The mass of the earth, 
Explanation:
It is given that,
Time taken by the moon to orbit the earth, 
Distance between moon and the earth,
We need to find the mass of the Earth using Kepler's third law of motion as :




So, the mass of the earth is
. Hence, this is the required solution.
Answer:
b) 338 N
Explanation: let m be the mass of the gymnast and a be the acceleration of the gymnast.
the force required to accelerate the gymnast is given by:
F = m×a
= (45.0)×(7.50)
= 337.5 N
Therefore, the force a trampoline has to apply is 138 N.
I think the correct answer would be to electrolyze water (run an electric current through it) to decompose it into hydrogen and oxygen. Assuming 100% efficiency, it is said that it needs about 40kWh per kilogram of water to fully decompose it.
The answer is D. As the ambulance gets closer, the sound waves are compressed relative to the person; so the frequency increases.
The correct answers are <span>starting friction and </span>static friction
Friction slows down all forces, but starting friction slows down or stops completely the start of motion.