Question

A point size body is moving along a circle at an angular velocity $2.8rad{s}^{-1}$. If centripetal acceleration of body is $7m{s}^{-2}$ then its speed is

• A. $1.25m{s}^{-1}$
• B. $2.5m{s}^{-1}$
• C. $3.5m{s}^{-1}$
• D. $7m{s}^{-1}$

Answer 1

The correct option is B $2.5m{s}^{-1}$

We know $a=\frac{v^2}{R}=$ centripetal acceleration.

We know $v=wR$

so $a=w^{2}R$

$\Rightarrow 7={\left(2.8\right)}^2\times R$

$\Rightarrow R=\frac{7}{{\left(2.8\right)}^2}$

so, $v=2.8\times \frac{7}{{\left(28\right)}^2}$

$\Rightarrow v=2.5m/s$

Hence, the answer is $2.5m/s.$