physicsa.com
class code: SPS22-10 teacher: Mr. Elert
classroom: 319 office: A214
test day: Friday phone: (718) 724-8500 ext. 2141
office hours: 8:05–2:40 email: [email protected]

Physics A: Problem Set 18: Friction

recommended reading

High Marks: 1:107–1:108
Barron's Let's Review: 3.8 Frictional forces, 3.9 The coefficient of friction
physics.info: Friction
Wikipedia: Friction
HyperPhysics: Friction
Khan Academy: Intuition on static and kinetic friction comparisons, Static and kinetic friction example, What are the forces of static and kinetic friction?
Physics Girl: Friction
Mr. Machado: 08 Friction and the coefficient of friction

classwork

  1. A wooden pallet carrying a load of 600 kg rests on a wooden floor. A forklift driver decides to push it without lifting it.
    1. Draw a free body diagram showing all the forces acting on the pallet.
    2. What is the weight of the loaded pallet?
    3. What is the normal force of the floor on the pallet?
    4. What force must be applied by the forklift to overcome static friction and start the pallet moving?
    A bit later, the pallet begins to slide. The forklift continues pushing the pallet with the force calcluated in part d.
    1. What is the new force of friction between the pallet and the floor?
    2. Determine the net force on the pallet.
    3. Determine the acceleration of the pallet.
    4. How fast is the pallet moving after two seconds?
    The forklift stops pushing the pallet and it slides away from the forks.
    1. What is the new net force on the pallet?
    2. Determine the acceleration of the pallet.
    3. Determine the time it takes the pallet to stop sliding.
    4. Determine the distance it takes the pallet to stop.