Search results
Review the units of work, energy, force, and distance. Use the equations for mechanical energy and work to show what is work and what is not. Make it clear why holding something off the ground or carrying something over a level surface is not work in the scientific sense.
- 15.1 The Electromagnetic Spectrum
Teacher Support [BL] Explain that the term spectrum refers...
- 22.4 Nuclear Fission and Fusion
As shown in Figure 22.26, a neutron strike can cause the...
- 23.1 The Four Fundamental Forces
Explain how particle accelerators work to gather evidence...
- 11.1 Temperature and Thermal Energy
Since heat, like work, transfers energy, it has the SI unit...
- 22.1 The Structure of The Atom
In addition, the High School Physics Laboratory Manual...
- 23.3 The Unification of Forces
As discussed earlier, the short ranges and large masses of...
- 21.3 The Dual Nature of Light
Figure 21.10 shows a comet with two prominent tails. Comet...
- 15.1 The Electromagnetic Spectrum
Both force and displacement are vectors. The work done is given by the dot product of the two vectors, where the result is a scalar. When the force F is constant and the angle θ between the force and the displacement s is also constant, then the work done is given by: If the force is variable, then work is given by the line integral:
Work is the energy needed to apply a force to move an object a particular distance, where force is parallel to the displacement. Power is the rate at which that work is done.
Examples of work include lifting a box against gravity (work done against gravity), pushing a car along a flat road (work done to overcome friction), and stretching a spring (work done to store elastic potential energy).
Figure \(\PageIndex{1}\): Examples of work. (a) The work done by the force \( F\) on this lawn mower is \(Fd \, cos \,\theta\). Note that \(F \, cos \, \theta\) is the component of the force in the direction of motion.
Figure 7.2 Examples of work. (a) The work done by the force F F on this lawn mower is Fd cos θ Fd cos θ. Note that F cos θ F cos θ is the component of the force in the direction of motion. (b) A person holding a briefcase does no work on it, because there is no displacement. No energy is transferred to or from the briefcase.
In physics, work represents a type of energy. Work is done when a force acts on something that undergoes a displacement from one position to another. Forces can vary as a function of position, and displacements can be along various paths between two points.
