Question

A point moves along a circle having a radius 20 cm with a constant tangential acceleration 5 $cm{s}^{-2}$. How much time is needed after motion begins for normal acceleration of the point to be equal to tangential acceleration?

• A. $1s$
• B. $2s$
• C. $3s$
• D. $4s$

Answer 1

The correct option is B $2s$

$v=u+a_{t}tv=0+5t=5tnowcentripetalaccelerationor{a}_n=\frac{v^2}{r}=\frac{25t^2}{20}=\frac{5t^2}{4}now,a_n=a_t\frac{5t^2}{4}=5t^2=4s\therefore t=2s$