1.) A box made of wood is sitting on a wooden floor. The box and contents...

1.) A box made of wood is sitting on a wooden floor. The box and contents has mass 40kg. The coefficient of static friction is 0.50 and kinetic friction is 0.30. A person begins to push the box horizontally by slowly increasing their force until it reaches 160N. Describe the state of motion (if any) of the box and the frictional force acting.

2.) The formula for friction is f=uN, for both static and dynamic friction. What factors that may effect the force of friction that are not listed in this equation. List three if you can and discuss them briefly.

Solutions

Expert Solution

1. The friction force(f) between the box and the surface =_sN =_smg [Note that the box is initially in static position.That's why we have to use static friction coefficient(_s) not the dynamic/kinetic friction coefficient(_k)]

f= (0.50)(40)(9.8)N = 196N .We must overcome this friction force in order to move the box.

Since the applied force is less than 196N , the box remains stationary.

Friction force (when external force=160N) =160N

2.The factors that may affect the force of friction are:

Nature of surface in contact : Friction between surface in contact is less for smooth surfaces and more for rough surfaces.
Friction force is different for different state of motion.(for the same object)
f=_sN when the object is at rest. And f= _kN when the object is moving relative to surface.
Friction force depends on the force pushing the two surfaces together.
A point worth noting is, friction always prevents relative motion between two surfaces in contact.

genius_generous answered 1 month ago

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