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 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.
    

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 5.0 kg missle is projected from rest to a speed of 4.5 x 10³ m/s. How much time is required to do this by a net force of 5.3 x 10⁵ N?

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?

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?

1.A horizontal force of 10N is applied to a 30 kg cart on a level floor. 

1. How far will it move in 3.0s, starting from rest? Ignore friction. 
2. How far will it move in 3.0s if 30N of groceries is added to the cart first?

A 50 kg sled starts at rest, and is being pushed across a horizontal frictionless surface with a force of 30 N. The wind is pushing against the sled. The sled travels 100 meters while accelerating to 10 m/s. What is the force of the wind on the sled?

After Luke Skywalker got his X-Wing fighter out of the swamp on Dagobah, he wanted to make it fly. The mass of the ship is 5,000 kg. Luke applies (using the force) an upward force of x Newtons. Yoda, who doesn't want Luke to get too confident, applies a downward force which is two-thirds of Luke's force.

Luke's Skywalker X-Wing fighter lifts off to a height of 2 km in 5 seconds. How much force did Luke apply?

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

 

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?