Earth's atmosphere is important because it contains oxygen without which we wouldn't be alive. It also prevents harmful rays from space or smaller meteors from entering and reaching Earth.
According to the work-energy theorem, the work done on an object by a net force equals the change in kinetic energy of the object. Essentially kinetic energy is the energy used for motion. Interestingly, as work is done on an object, potential energy can be stored in that object. A moving object has kinetic energy because work has been done on it. When work is done energy in one form is transferred to the kinetic energy of the moving object. To stop the object again, the same amount of work would have to be done to bring it back to rest.
Answer:
Calculating acceleration involves dividing velocity by time — or in terms of SI units, dividing the meter per second [m/s] by the second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared .
-- The product of their two masses (no matter what
the individual masses happen to be),
-- The distance between the centers of mass of the two masses.
Nothing else affects the force of gravity between two objects,
and nothing in between them can 'shield' or block it.
That's the period of time that we call a "year".
It's roughly 365.24 days.
