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5.Work, Energy, Power and Collision
medium
The kinetic energy of a body moving along a straight line varies with time as shown in figure. The force acting on body
A
zero
B
constant
C
direct by proportional to velocity.
D
inversely proportional to velocity.
Solution
$\frac{1}{2} m v^{2} \propto t$
$\mathrm{v} \propto \sqrt{\mathrm{t}}$
$\Rightarrow \mathrm{v}=\alpha \sqrt{\mathrm{t}}$
$a=\frac{d v}{d t}=\frac{\alpha}{2} t^{-1 / 2}=\frac{\alpha}{2 \sqrt{t}}$
$F=m a=\frac{m \alpha}{2 \sqrt{t}}$
$\mathrm{F} \propto \frac{1}{\mathrm{v}}$
Standard 11
Physics
