The kinetic energy is .
Explanation:
The kinetic energy of an object is given by
where
K is the kinetic energy of the object
m is the mass of the object
v is the speed of the object
For the comet in this problem, we have:
is its mass
is the speed
First, we convert the speed from km/h to m/s:
Therefore, the kinetic energy of the comet is
Learn more about kinetic energy here:
#LearnwithBrainly
Given,
Distance from the surface to the center of the earth, d=4000 miles
Distance from the center to you at a height of 8000 miles, a= 8000+4000=12000 miles
The gravitational force acting on a person at the surface is equal to his weight.
From Newton's Universal Law of Gravitation, the gravitational force is
Where G is the gravitational constant, M is the mass of the earth, m is the mass of the object/person, r is the distance between the center of the earth and the object/person
At the surface, this force is equal to the weight of the person, W=mg
i.e.
On substituting the of d,
At a height of 8000 miles from the surface, the gravitational force is equal to,
On dividing the above two equations,
Therefore,
Therefore at a height of 8000 miles above the surface of the earth, the force of gravity becomes 1/9 time your weight.