Question

In which one of the following situations is the net force constantly zero on the object?

(A) A mass attached to a string and swinging like a pendulum. 

(B) A stone falling freely in a gravitational field. 

(C) An astronaut floating in the International Space Station. 

(D) A snowboarder riding down a steep hill. 

(E) A skydiver who has reached terminal velocity

Answer 1

Correct option (E) A skydiver who has reached terminal velocity.

Changing direction (choices A and C (the astronaut is still orbiting the earth!)) cannot occur with a zero net force. Choices B and D represent accelerated motion.