Passage II

When a sphere falls through air, the sphere is subjected to a drag force, F, that resists its motion. F depends on the spheres diameter, D; the air temperature, T; the sphere's speed, V; and atmospheric pressure.

The table below gives F, in newtons(N), on a sphere falling through air near Earth's surface, for various combinations of D, in meters (m); T, in degrees Celsius (°C); and V, in meters per second (m/sec). For each combination, air pressure is 1 atmosphere.

10. As a sphere moves as described in the passage, a transformation of energy takes place involving the sphere’s kinetic energy (KEs), the sphere’s potential energy due to Earth’s gravity (GPEs), and heat (Q). Which of the following statements best describes this transformation?

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Energy is conserved, the initial velocity of the ball is 0 at the moment of falling, so there is no kinetic energy KE; the total mechanical energy TME is the gravitational potential energy PE of the ball at this time. During the falling process, due to the acceleration of gravity, the speed increases and the kinetic energy KE increases (potential energy PE is converted into internal energy Q). At the same time, the resistance will also convert part of the mechanical energy into internal energy Q