Question

A particle moves along a circle of radius $\left(\frac{20}{\pi}\right) m$ with constant tangential acceleration. If the velocity of the particle is $80\, m/s$ at the end of the second revolution after motion has begun, the tangential acceleration is

• A. 40 $m/s^2$
• B. 640 $\pi \, m/s^2$
• C. 160 $\pi \, m/s^2$
• D. $40\, \pi \, m/s^2$

Answer 1

Answer: (A)

40 $m/s^2$

Answer 2

$r =\frac{20}{\pi}$
In two revolution, distance is $s =2 \times 2 \pi r =80 m$
Now, $v ^{2}=2$ as for zero initial speed.
$\Longrightarrow a =\frac{ v ^{2}}{2 s }=\frac{80 \times 80}{2 \times 80}$
$\Longrightarrow a =40 m / s ^{2}$