Question

 

1.

What forces are acting on the object as it moves?

2.

What are the effects of gravity on the object?

3.

Describe the role and effect of static friction and

kinetic friction in the machine.

4.

Find the coefficient of static friction as the object

begins to move.

 

Answer 1

1] To understand the motion of the object, the forces on it must be analyzed. The net force on it will determine its motion along a given direction. If the net force on it is zero in all directions, the forces are getting cancelled and the object will be either at rest or in a uniform velocity motion.

2] The effects of gravity can be understood by first observing if the vertical force due to gravitational acceleration is causing net motion along the vertical direction. Second, if this force is creating a non-zero torque on the object. The gravitational force will be proportional to the mass of the object (F = mg).

3] If the object is resting on a surface, the coefficient of static friction between the surface and the object will determine the minimum force required to begin its motion. The friction force will be given by: .

Once in motion, the frictional force reduces to where the coefficient of kinetic friction comes into play which is lesser than the coefficient of static friction.

4] For an object at rest, determine the minimum horizontal force required by the object to begin moving. In the absence of other force, this minimum required force will be equal to the frictional force. Use this to determine the coefficient of static friction by using the relation ..