Newton's Third Law & Action-Reaction Pairs Practice Problems

During a physics experiment, blocks P and Q are placed on a horizontal, frictionless working bench. The masses of the blocks are P = 35 kg and Q = 15 kg respectively. Block P is pushed with a horizontal force of 360 N. Determine the magnitude of the force that block P applies to block Q. 

The starting blocks used by sprinters give them a nearly horizontal acceleration. A 58.0 kg sprinter using a starting block has a nearly horizontal acceleration with a magnitude of 14.5 m/s². 

a) Determine the horizontal force the sprinter has to exert on the starting blocks to generate the acceleration.

b) The sprinter is propelled forward by a force from: i) the sprinter himself ii) the blocks.

A 1200kg stalled truck on a level parking lot is pushed by a small SUV of mass of 650 kg in a direction due north. The SUV is pushing on the truck with a 2200 N horizontal force. Determine the magnitude of the force applied to the SUV by the truck.