Forces in Equilibrium - Practice Problems

 For each problem:   1.    Draw a freebody diagram. 2.    Draw in the x- and y- axes. 3.    Resolve each vector not already on the x- or y-axis into its x- and y- components. 4.    Write an equation for the sum of forces in the x- and y-direction. If the system is at rest or constant velocity, the net force is zero. 5.    Put your givens into the equations and solve for the unknowns.

Ø        A 10.0 kg mass hangs from two strings, each making an angle of 35.0° with the ceiling.  What is the tension in each string? Solution

Ø        A 15.0 kg block is at rest on a 40.0° incline.  Find the magnitude of the normal force and the friction. Solution

Ø        A 25.0 kg wagon and rider is being pulled at constant velocity with a force of 50.0 N directed along the handle.  The handle makes an angle of 65.0° with the horizontal.  Find the magnitude of the normal force and the force of friction. Solution

Ø        A 20.0 kg lawn mower is being pushed at constant velocity with a force of 65.0 N directed along the handle.  The handle makes an angle of 60.0° with the horizontal.  Find the magnitude of the normal force and the force of friction. Solution

Ø        Honors problem: Find the tensions in strings 1 and 2 supporting a 20.0 N rock hanging from the ceiling. Strings 1 and 2 make angles of 30.0° and 40.0° with the ceiling, respectively. Solution