A Fireman Is Sliding Down a Fire Pole

Multiple Choice

A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the pole exerts on the fireman. When this force equals the weight of the fireman, which of the following happens?

A) The fireman comes to a stop.
B) The fireman descends at slower and slower speed.
C) The fireman descends with a smaller acceleration.
D) The fireman continues to descend, but at a constant speed.