Answer to Question #141531 in Mechanics | Relativity for Mac Roy

Question

During the time between a parachutist leaving a plane and reaching the ground safely
1 the sum of her gravitational potential energy and her kinetic energy is constant
2 her kinetic energy depends upon her velocity
3 her gravitational potential energy is proportional to her height above the ground
Which of A, B, C, D, E shows the correct answers?
A 1, 2., 3 B 1, 2 C 2, 3 D 1 only E 3 only
Explain the reasons for your choice

Answer 1

K+U is constant by the law of conservation of energy.

And $K=\frac{mv^2}{2}.$

And $U=mgh.$

So A (1, 2, 3) is correct.