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2.Motion in Straight Line
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The initial velocity of a particle is $u\left(\right.$ at $t=0$ ) and the acceleration a is given by $\alpha t^{3 / 2}$. Which of the following relations is valid?
A
$v=u+\alpha t^{3 / 2}$
B
$v=u+\frac{3 \alpha t^3}{2}$
C
$v=u+\frac{2}{5} \alpha t^{5 / 2}$
D
$v=u+\alpha t^{5 / 2}$
Solution
(c)
$a=\alpha t^{3 / 2}$ (acceleration is a function of time)
$\int \limits_u^v d v=\int \limits_0^t a d t$
$\Rightarrow \int \limits_u^v d v=\int \limits_0^t \alpha t^{3 / 2} d t$
$\left.\Rightarrow v\right|_u ^v=\left.\alpha \frac{t^{3 / 2}+1}{\frac{3}{2}+1}\right|_0 ^t$
$\Rightarrow (v-u)=\alpha \times \frac{2}{5} \quad\left(t^{5 / 2}-0\right)$
$\Rightarrow v-u=\frac{2}{5} \alpha t^{5 / 2}$
$\Rightarrow v=u+\frac{2}{5} \alpha t^{5 / 2}$
Standard 11
Physics
Similar Questions
In the $s-t$ equation $\left(s=10+20 t-5 t^2\right)$, match the following columns.
Colum $I$ | Colum $II$ |
$(A)$ Distance travelled in $3\,s$ | $(p)$ $-20$ units |
$(B)$ Displacement in $1\,s$ | $(q)$ $15$ units |
$(C)$ Initial acceleration | $(r)$ $25$ units |
$(D)$ Velocity at $4\,s$ | $(s)$ $-10$ units |
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