Howard is standing in the middle of a skating rink (we'll assume no friction), and his four friends Alice, Bernie, Christopher, and David approach him from each of the four compass directions - north, east, south, and west, respectively.

Alice pushes on Howard with a force of x + 20 Newtons. Bernie pushes on him with a force of 2x + y Newtons. Christopher pushes on him with a force of 2x - y Newtons, and David pushes with a force of 5y Newtons.

Howard, though being pushed from all directions, does not move. Calculate the forces being applied in all four directions.

A force is applied to a 1000 kg car, and causes the car to accelerate from 0 m/s to 25 m/s while traveling 200 m. The same force is applied to a 600kg motorcycle.  How far will the motorcycle travel while accelerating from 10 m/s to 40 m/s?

If a force accelerates 4.5 kg at 40 m/s², that same force would accelerate 18 kg by how much?

A mass, m₁, accelerates at 3 m/s² when a force, F, is applied. A second mass, m₂, accelerates at 1.0 m/s² when F is applied to it.

1. Find the value of the ratio m₁/m₂.
2. Find the acceleration of the combined mass ( m₁ + m₂) under the action of the force, F.
    

An elevator has a mass of 2,000 kg.  An upward force of 21,000 Newtons is applied to the elevator. The elevator travels up 50 floors, and each floor is 2.5 meters tall, with a 20 centimeter gap between floors. How long does it take the elevator to arrive, and at what speed will it be traveling?

A 1000-kg car moving north at 100km/h brakes to a stop in 50m. What are the magnitude and direction of the force?

 

A hockey stick travels backward 11.0 cm while intercepting a 0.140 kg puck. How much force did the stick exert on the puck to bring the puck from 35.0 m/s to rest?

A 6000 kg tractor rests on a flatbed, held in place by chains. The chains provide a maximum horizontal force of 8000 N. When the flatbed is traveling 20 m/s, what is the minimum stopping distance if the chains are not to break?

If the coefficient of kinetic friction between a 35 kg crate and the floor is .30, what horizontal force is required to move the crate at a steady speed across the floor? What horizontal force is required if µ_k is zero?

A car accelerates from 10 m/s to 50 m/s while traveling 400 m. The mass of the car is 1500 kg. What force was applied to the car?

Four passengers with mass 85 kg apiece are added to the problem above, how much would that change the force required?