The work done by a force on a body of mass 5 | vedclass

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Question

(B) The correct option is $B$.Concept: According to the work-energy theorem, the total work done by all forces acting on a body is equal to the change

Vedclass · Accepted Answer

$10^3 \,J$

Vedclass · Answer

(B) The correct option is $B$.Concept: According to the work-energy theorem, the total work done by all forces acting on a body is equal to the change in its kinetic energy $(K.E.)$.Given: Mass $m = 5 \,kg$, initial velocity $u = 0 \,m/s$, final velocity $v = 20 \,m/s$.Work done $W = \Delta K.E. = K.E._{final} - K.E._{initial}$.$W = \frac{1}{2} mv^2 - \frac{1}{2} mu^2$.$W = \frac{1}{2} 	imes 5 	imes (20)^2 - 0$.$W = \frac{1}{2} 	imes 5 	imes 400 = 5 	imes 200 = 1000 \,J = 10^3 \,J$.

The work done by a force on a body of mass $5 \,kg$ to accelerate it in the direction of the force from rest to $20 \,m/s$ in $10 \,s$ is:

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