Question

In which of the following motions does the work/kinetic energy theorem apply?

a. Circular orbit
b. Elliptical orbit
c. Parabolic orbit
d. Hyperbolic orbit
e. Falling on a straight line into the Sun
f. All of these motions

Answer 1

well, think about the Kinetic energy formula: \(\sf \color{red}{KE = \frac{1}{2}mv^2}\)
where
m = mass
v = velocity

this tells you that kinetic energy is proportional to the product of the mass and velocity squared.
So, as you increase in one, the other must also increase. Does that make sense?