Friction & the Inclined Plane

Name: _____________________

DATE: Sept 19 2002

  1. A cross-country skier and her skies have a total mass of 53.6 kg. If it takes a horizontal force of 37.5 N to start moving on wet snow on level ground, calculate the coefficient of static friction for the skies on wet snow.

  2. A lift truck with rubber tires has a mass of 1640 kg. What is the force of kinetic friction when the lift truck skids on wet concrete with all four wheels locked?
    Coefficient of friction between wet concrete and rubber is 0.512

  3. A 12.3 kg mass rests on an inclined plane. Calculate the angle of repose if the coefficient of friction between this object and the inclined plane is 0.262.

  4. A steel dumpster of mass 1200 kg is being lowered down a hill with a 19.5o grade. If the coefficient of friction between the dumpster and the hill is 0.713 determine the following:
    1. The force of friction retarding the motion of the dumpster down the hill.
    2. The force needed to keep the dumpster sliding down the hill at a constant, controlled rate of speed.

  5. An incline plane between the ground and the back of a truck is inclined at an angle of 28.5o. A frig is being pushed up the ramp onto the truck. The mass of the frig is 86.5 kg and the coefficient of friction ( μ) between the ramp and the frig is 0.466. Calculate the following:
    1. The force needed to push the frig up the ramp if there was no friction.
    2. The force needed to lift the frig staight up.
    3. The normal force that the frig exerts on the ramp.
    4. What is the mechanical advantage generated by the ramp.
    5. The force of friction between the ramp and the frig.
    6. The actual force that would be needed to move the frig up the ramp and onto the truck.
    7. How does friction affect the mechanical advantage of the ramp?

  6. A horizontal force of 12.3 N is applied to a 5.67 kg object causing it to move 12.3 m. in a horizontal direction
    a) Calculate how much work is done on this object.
    b) If this same object was to be lifted 2.6m, how much work would have to be done, to lift
         object straight upward?

Version Two

Friction & the Inclined Plane

Name: _____________________

DATE: Sept 26 2002

  1. A wagon and its load have a total mass of 73.3 kg. If it takes a horizontal force of 24.5 N to start moving on level side, calculate the coefficient of static friction for this wagon.

  2. The coefficient of friction between wet concrete and rubber is 0.512. The force of kinetic friction generated by the brakes of a lift truck when it skids on wet concrete with all four wheels locked is 8140 N. Calculate the mass of this lift truck.

  3. A 22.3 kg mass rests on an inclined plane. Calculate the angle of repose if the coefficient of friction between this object and the inclined plane is 0.462.

  4. A steel dumpster of mass 1450 kg is being lowered down a hill with a 22.5o grade. If the coefficient of friction between the dumpster and the hill is 0.316 determine the following:
    1. The force of friction retarding the motion of the dumpster down the hill.
    2. The force needed to keep the dumpster sliding down the hill at a constant, controlled rate of speed.

  5. An incline plane between the ground and the back of a truck is inclined at an angle of 26.7o. A filing cabinet is being pushed up the ramp onto the truck. The mass of the filing cabinet is 72.3 kg and the coefficient of friction ( μ) between the ramp and the filing cabinet is 0.506. Calculate the following:
    1. The force needed to push the filing cabinet up the ramp if there was no friction.
    2. The force needed to lift the filing cabinet straight up.
    3. The normal force that the filing cabinet exerts on the ramp.
    4. What is the mechanical advantage generated by the ramp.
    5. The force of friction between the ramp and the filing cabinet.
    6. The actual force that would be needed to move the filing cabinet up the ramp and onto the truck.
    7. How does friction affect the mechanical advantage of the ramp?

  6. A horizontal force of 32.3 N is applied to a 5.67 kg object causing it to move 17.3 m.
    a) Calculate how much work is done on this object as it moves horizontally.
    b) If this same object was to be lifted 2.6m, how much work would have to be done, to lift
         object straight upward?