Answer:
Gravitational force
Explanation:
If two spheres have equal densities and they are subject only to their mutual gravitational attraction. We need to say that the quantities that must have the same magnitude for both spheres. So, the correct option is (E) i.e. gravitational force.
It is because of Newton's third law of motion. It states that the force due to object 1 to object 2 is same as force due to object 2 to object 1. The two forces act in opposite direction.
Hence, the correct option is (E) "Gravitational force".
Mass x Force of gravity = Weight
Weight is a force.
On Earth, the force due to gravity is ~9.81 N/Kg. So an object of 100 Kg will have a weight of ~981 N
The acceleration of the car will be needed in order to calculate the time. It is important to consider that the final speed is equal to zero:

We can clear time in the speed equation:

If you find some mistake in my English, please tell me know.
True.
Depending how accurate the graph is plotted