The centripetal force is the gravitational force of attraction between the Earth and the Moon.
Also, the gravitational force of attraction between the Earth and the Sun is the centripetal force that causes the Earth to stay in orbit around the Sun.
Also, the gravitational force of attraction between a TV satellite, a weather satellite, or a GPS satellite and the Earth is the centripetal force that causes each satellite to stay in orbit around the Earth.
Answer:
The speed of the wind is 25 km/hr.
Explanation:
Let us call 
the speed of the plane and 
the speed of the wind. When the plane is flying against the wind, it covers the distance of 900-km in 2 hours (120 minutes); therefore;
(1). 
And when the plane is flying with the wind, it covers the same distance in 1 hour 48 minutes (108 minutes)
(2). 
From equation (1) we solve for and get:
,
and by putting this into equation (2) we get:
or in km/hr this is
Um, this doesn't make any sense. By climbing a hill, you are decreasing your momentum and kinetic energy, so it slows you down. The only positive, is after you have climbed the hill, you have more potential energy, and it will be released once you go down the hill, but you will not be as fast as if you ignored the hill.
Because gravity accelerates all objects the same regardless of their mass
A) Energy is absorbed in the reaction.
Such reactions are called endothermic reactions.
