Unit 4 Activity 4 Extension D Quiz

You have seen that the effect of the drag force on a skydiver is to make him speed up at a slower and slower rate as he falls, until he reaches his terminal velocity. Which of the speed-time graphs below shows this behavior?

A.

As the elevator passes the second floor, it starts to slow down so that it can stop at the first floor. While it is slowing down as it descends, how would the forces acting on the elevator compare?

A. The upward force of the cable would be stronger than the downward gravitational force.

As it passes the 9th floor, the elevator reaches the desired descent speed and so travels from here down to the 2nd floor at a constant speed. While it is moving downward at a constant speed, how would the forces acting on the elevator compare?

B. The upward force of the cable would be equal in strength to the downward gravitational force

Imagine an empty elevator is making a trip down from the 10th floor to the 1st floor of a building. The following three questions concern various stages in this journey.The elevator starts at rest on the 10th floor and then starts to move downward, speeding up as it does so. While this is happening, how would the forces acting on the elevator compare?

C. The upward force of the cable would be weaker than the downward gravitational force.