PHY 131 Chapter Notes - Chapter 8: International System Of Units, Situation Two, Conservative Force

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roseox281

12 Oct 2017

School

Stony Brook University

Department

Physics

Course

PHY 131

Professor

Clark Mc Grew

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PHY 131 Full Course Notes

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Document Summary

We are going to categorize forces into two types: conservative and nonconservative forces. A conservative force can be a function of only of position and cannot depend on other variables like time or velocity. We can give the definition of a conservative force in another, completely equivalent way: a force is conservative if the net work done by the force on an object moving around any closed path is zero. The work done by nonconservative force depends on the path. Potential energy is the energy associated with forces that depend on the position or configuration of objects relative to the surroundings. The most common example of potential energy is gravitational potential energy. We can define the change in gravitational potential energy u when an object moves from a height y1 as equal to the work done by a net external force to accomplish this without acceleration:

Related Questions

Which of the following statement are true mechanical energy? Include all that apply.

1.The total amount of mechanical energy of an object is the sum of its potential energy and the kinetic energy.

2. Heat is a form of mechanical energy.

3. The mechanical energy of an object is always conserved.

4. When non-conservative forces do work, energy is transformed from kinetic to potential (or vice versa), but the total mechanical energy is conserved.

5. A bowling ball is mounted from a ceiling by way of a strong cable. It is a drawback and released, allowed to swing as a pendulum. As it swings from its highest position to its lowest position, the total mechanical energy is mostly conserved.

6. When a friction force does work on an object, the total mechanical energy of that object is changed.

7. The total mechanical energy of an object remains constant if the only forces doing work on the object are conservative forces.

8. If an object gains mechanical energy, then one can be certain that a non-conservative force is doing work.

lilacplatypus580

(a) Suppose a constant force acts on an object. The force does not vary with time or with the position or the velocity of the object. Start with the general definition for work done by a force

and show that the force is conservative,

(b) As a special case, suppose the force acts on a particle that moves from O to (C) in Figure P7.43. Calculate the work done by on the particle as it moved along each one of the three paths shown in the figure and show that the work done along the three paths identical.

erinserval647

(a) Suppose a constant force acts on an object, The force does not vary with time or with the position or the velocity of the object. Start with the general definition for work done by a force:

and show that the force is conservative.

(b) As a special case, suppose the force acts on a particle that moves from O to c in Figure P7.43. Calculate the work done by F on the particle as it moves along each one of the three paths shown in the figure and shows that the work done along the three paths are identical.