A 43.2 kg video cart is rolled down a hallway. It is accelerated at 0.30 m/s^2. If a force of 27 N is applied to move the cart, what force of friction do the wheels have against the floor?

A 51.9 kg crate is hung from the ceiling by two wires. Each wire makes an angle of 41 degrees with the ceiling. What is the tension (in newtons) in one of the wires?

Two blocks A and B with mA = 1.1 kg and mB = 0.88 kg are connected by a string of negligible mass. They rest on a frictionless horizontal surface. You pull on block A with a horizontal force of 6.7 N. How will the tension in the string be affected if mA is decreased?

You are pushing a wooden crate against a rubber floor. The two surfaces have a static coefficient of friction of 0.45 and a kinetic coefficient of friction of 0.38. The floor is horizontal, and the crate has a mass of 25.0 kg, and is initially at rest. You are pushing with a horizontal force of 155 N. What is the magnitude of the force of friction in this case? Give your answer in units of N, to three significant figures.