Solution: A 165 lb researcher received a shipment of lab equipment in a 1600 N crate. She pushes it across the floor applying a 115 N force with her hands. Which of the following is true? A) She always feels a 115 N force from the crate pushing back against her hands. B) The crate will push back at her with a force of 165 lb. C) She will feel a 1600 N force from the crate pushing back at her. D) Only if the crate does not move will she feel a force of 115 N. E) She will feel it pushing back at her with less than 115 N, if the crate is moving forward.

Problem

A 165 lb researcher received a shipment of lab equipment in a 1600 N crate. She pushes it across the floor applying a 115 N force with her hands. Which of the following is true?

A) She always feels a 115 N force from the crate pushing back against her hands.

B) The crate will push back at her with a force of 165 lb.

C) She will feel a 1600 N force from the crate pushing back at her.

D) Only if the crate does not move will she feel a force of 115 N.

E) She will feel it pushing back at her with less than 115 N, if the crate is moving forward.