: In order to push a pile of crates forward, a student applies a force. There is a friction
force that pushes backward on the crates with a magnitude half as much as the force
from the student. If the student pushes with a force of 300 N to the right, the net
force on the crates will be ---

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?