PHYSICS CHAP. 11 WORK AND ENERGY (FA 3)
The two conditions needed to satisfy the work being done are (i) A force should act on an object, and
(ii) The object must be displaced.
If any one of the above conditions does not exist, work is not done. This is the way work is viewed in science. Work
Let a constant force, F act on an object. Let the object be displaced through a distance, s in the direction of force. Let W be the work done. We define work to be equal to the product of the force and displacement. Work done = Force × Displacement
W = F s = mg × s
Thus, work done by a force acting on an object is equal to the magnitude of force acting on an object is equal to the magnitude of force multiplied by the distance moved in the direction of the force. Work has only magnitude and no direction. If F = 1 N and s = 1 m then the work done by the force will be 1 N m. Here the unit of work is newton metre (N m) or joule (J). Thus, 1 J is the amount of work done by an object when a force of 1 N displaces it by 1 m along the line of action of the force. The work done by force can either be positive or negative. When the angle between two directions is 1800, the work done by the F is taken as negative and denoted by minus sign. The work done by force is F × (-s) or (-F × s) Energy
An object having a capability to do work is said to possess energy. An object that possesses energy can exert a force on another object. An object that possesses energy can do work. 1 J is the energy required to do 1 J work. Kinetic Energy -
Objects in motion possess energy. This energy is called kinetic energy. The kinetic energy of an object increases its speed. Ek = 1/2 mv2 is the work done of an object when the initial velocity, u is 0. Or Ek = 1/2 m (v2-u2)
Potential Energy -
The potential energy possessed by the object is the energy present in it by virtue of its position or configuration....
Please join StudyMode to read the full document