Question

A motor car is travelling at 60 m/s on a circular road of radius 1200 m. It is increasing its speed at the rate of 4 $m/s^2$. The acceleration of the car is:

• A. 3 $m/s^2$
• B. 6 $m/s^2$
• C. 5 $m/s^2$
• D. 7 $m/s^2$

Answer 1

The correct option is C 5 $m/s^2$

Given,

$a_t=4m/s^2$

$v=60m/s$

$r=1200m$

Radial acceleration, $a_r=\frac{v^2}{r}$

$a_r=\frac{60\times 60}{1200}=3m/s^2$

The acceleration of the car is

$a=\sqrt{(a_t{)}^2+(a_r{)}^2}$

$a=\sqrt{(4{)}^2+(3{)}^2}=\sqrt{25}$

$a=5m/s^2$

The correct option is C.