Question

A particle is moving along a circular path of radius $5 \,m$ with a uniform speed $5\, ms^{ - 1 }$ What will be the average acceleration when the particle completes half revolution ?

• A. Zero
• B. $10\,ms^{ - 2 }$
• C. $10 \,\pi\, ms^{ - 2 }$
• D. $\frac{ 10 }{ \pi } ms^{ - 2 }$

Answer 1

Answer: (D)

$\frac{ 10 }{ \pi } ms^{ - 2 }$

Answer 2

When the particle completes half revolution, change in velocity
$\triangle v=[5-(-5)] \,m s^{-1}=10\, ms ^{-1}$
Time taken to complete the half revolution is
$t =\frac{\pi r}{v}=\frac{\pi \times 5}{5}=\pi$ second
Thus, average acceleration
$a_{v}=\frac{\Delta v}{t}=\frac{10}{\pi}\, m s^{-2}$