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Work,Power Energy, (physics), Er. Sunny, Kashyap, 1, W Edit with WPS Office

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Work:-Work done W is defined as the dot product of force F and displacements., W = Ē.3, = Fscos e, Here 0 is the angle between F and 5., Workdonebytheforceispositiveiftheanglebetweenforceanddisplacementisacute(0'<0<90)ascos eispositive. Thi, ssignifies,whentheforceanddisplacementareinthesamedirection,workdoneispositive. Thiswork is said to be, done uponthe body., When the force acts in a direction at right angle to the direction of displacement (cos 90° = 0), no work, isdone (zero work)., Workdonebytheforceisnegativeiftheanglebetweenforceanddisplacementisobtuse(90'<e<180')as cose, is negative. This signifies, when the force and displacement are in opposite directions, workdoneis, negative.This work issaid to be done bythe body., Workdoneby avariableforce:-, Ifappliedforce Fis not a constant force, then work done by this force in moving the body from position A to B, will be,, W = |F.ds, Here ds is the small displacement., Units:The unit of work done in S.l is joule (J) and in C.G.S system is erg., 1J = 1 N.m , 1 erg = 1 dyn.cm, Relationbetween Jouleand erg:-1 J =10'erg, Power:-The rate at which work is done is called power and is defined as,, P=W/t=F.s/V3DF.v, Here s is the distance and vis the speed., 2, W Edit with WPS Office

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Instantaneous power in terms of mechanical energy:- P = dE/ dt, Units:The unit of power in the S.I system isJ/s (watt) and in C.G.S system is erg/s., Energy:-, 1) Energy is the ability of the body to do some work. The unit of energy is the same as that of work., 2) Kinetic Energy (K):- It is defined as,, K=½mv, Heremisthemassofthebodyand visthespeedofthebody., Potential Energy (U):- Potential energy of a body is defined as, U = mgh, Here,misthe massofthe body,gis thefreefall acceleration(accelerationdueto gravity)andh istheheight., GravitationalPotentialEnergy:-, Anobject'sgravitationalpotentialenergy Uisitsmassmtimestheacceleration due to gravity g times its, height h above a zero level., Insymbol's,, U = mgh, Relation between Kinetic Energy (K) and momentum(p):-, K=p°/2m, Iftwobodiesofdifferentmasseshavethesamemomentum,abodywithagreatermassshallhavelesserkin, etic energy., Iftwobodiesofdifferentmasshavethesamekineticenergy,thebodywithagreatermassshallhavegreater, momentum., For two bodies having the same mass, the body having greater momentum shall have greater, kineticenergy., WorkenergyTheorem:-Itstatesthatworkdoneonthebodyorbythebodyisequaltothenetchangein its kinetic, energy ., For constant force,, W=½mv-½mư, = Final K.E - Initial K.E, For variable force,, 3, W Edit with WPS Office