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5.Work, Energy, Power and Collision
medium
A body of mass $10\,kg$ at rest is acted upon simultaneously by two forces $4 \,N$ and $3\,N$ at right angles to each other. The kinetic energy of the body at the end of $10 \,sec$ is .............. $\mathrm{J}$
A
$100 $
B
$300$
C
$50$
D
$125 $
Solution
(d)Net force on body$ = \sqrt {{4^2} + {3^2}} = 5N$
$a = F/m = 5/10 = 1/2\,m/{s^2}$
Kinetic energy = $\frac{1}{2}m{v^2}$$ = \frac{1}{2}m{(at)^2} = 125\,Joule$
Standard 11
Physics
