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5.Work, Energy, Power and Collision
normal
A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time $t^{\prime}$ is proportional to :
A
$t^{\frac{1}{4}}$
B
$t^{\frac{3}{4}}$
C
$t^{\frac{3}{2}}$
D
$t^{\frac{1}{2}}$
Solution
${P}=$ constant
$\frac{1}{2} m v^{2}=P_{t}$ $\Rightarrow v \propto \sqrt{t}$
$\frac{d x}{d t}=C \sqrt{t} \quad c=$ constant
$\frac{1}{2} m v^{2}=P_{t}$
$\Rightarrow v \propto \sqrt{t}$
by integration.
$x =C \frac{t^{\frac{1}{2}+1}}{\frac{1}{2}+1}$
$x\propto t^{3 / 2}$
Standard 11
Physics