Struggling with this. Can you help?

Unclear without more information

Explanation:

This is about transfer of energy. If you assume there is no energy lost to the environment (virtually impossible) - then all of the potential energy at the beginning would be transferred to kinetic energy along the route.

So, assuming that the rollercoaster has a velocity of 0 m/s at point A, then you can calculate the potential energy using:

At the point D, you would assume that the energy is split between some kinetic energy and some potential energy. So, we could say that the total energy is the sum of these:

If we assume all energy is transferred (ie. no energy lost to friction/heat etc) then we can equate these two and solve:

However, this answer seems unlikely given the drawing - which implies that there is perhaps more information that is missing??

your answer is c! hope this : )

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.