Can the normal force on an object ever do work? Explain?

Answer 1

No....

In order for an object to gain energy, work must be done on it by an external force. When work is done on an object by a force acting parallel to its displacement the formula is:

workdone = force x displacement

For positive work to be done, F and s must be parallel and pointed in the same direction. The unit used to measure work and energy is a joule. [J = kg m2/sec2 = Nm]

The normal force and the object's weight are in static equilibrium (they are balanced forces), the applied force, F, is an unbalanced force and will result in the object being accelerated across the top of the table's surface in the same direction as the force. This acceleration will change the object's velocity and subsequently its kinetic energy. We say that this applied force is doing work on the object. The amount of work done by F is directly proportional to the distance through which the force is applied as it pulls the object across the table's surface.

net Workdone = (net F)s

By using Newton's second law, net F = ma, our equation becomes :
net Workdone = (ma)s
net Workdone = m(as)

Remembering the kinematics equation vf2 = vo2 + 2as and solving for "as" let's our equation become:
net Workdone = m[½(vf2 - vo2)]
net Workdone = ½(mvf2 - mvo2)
net Workdone = ½mvf2 - ½mvo2
net Wdone = ΔKE

The relationship we just derived is called the energy-work theorem..

This statement tells us that when an external force does work on an object it will change the object's kinetic energy; that is, it will cause the object to either gain or lose speed. When more than one force is acting on an object, all forces that are either parallel or antiparallel to the direction the object moves will do work. If the object's velocity remains constant, that just means that the work done by opposing forces (for example, a forward applied force, F, and an opposing force, friction) are equal.

Note that if F and s are perpendicular to each other no work is done on the object. In our example of the block being dragged across the table, neither the normal force nor the weight would do any work on the block since they act at right angles to the direction of the block's motion. Another example would be when a satellite is being held in circular orbit by the force of gravity. Note that since the satellite's speed and orbital radius remain constant, no energy is being changed; therefore, no work is being done on the satellite.

Answer 2

Yes, think of what happens when you ride an elevator: the normal force on your feet increases and you start to rise relative to the rest of the building.

Answer 3

favourite rigidity is ninety stages to course of any action Static Friction rigidity: the object isn't shifting===> No paintings when you consider that paintings = rigidity * distance Kinetic friction does paintings because the object strikes