Question

summary of chapter 'work and energy'

Answer 1

work is said to be done when force is displaces a body through some result along its direction it is measured as the product of force and displacement work = force multiplied displacement energy is the total capacity of doing work is called energy forms of energy mechanical energy is classified as potential energy and kinetic energy potential energy means the energy for the body by virtue of its position and kinetic energy means the energy possessed by virtue of motion is called Kinetic energy heat energy magnetic energy light energy electrical energy chemical energy nuclear energy density is known as mass per unit volume unit is kg metre -3 is a scalar quantity positive negative and zero work done by a force can be positive negative or zero the work done is positive work is done at direction of motion of the body the negative work is said to be done when the force acts upon opposite direction Works is zero when a force at at right angles to the direction of the motion of the body transformation of energy energy can be transferred from one form to another form transducer A device which convert one form to another form example a cell converts chemical to electrical law of conservation of energy states that energy can be neither be created nor destroyed it can be transferred from one form to another form in the universe the energy is always constant power is the rate of doing work power equals to work t
practical unit of power is kilowatt = mm walls commercial unit of power is horsepower 746 walts practical unit of energy equals to kilowatt hour in the body most in different directions and direction of force the work done is given as work equals to force cos work is said to be done only when there is an along the direction of the force a Porter carry on his load does no work because the weight is always acting towards the centre of the earth along the direction of force there is no displacement