Question

J2
92. A car is driven round a curved path of radius
18m in without the danger of skidding. The
coefficient of friction between the tyres of the
car and the surface of the curved path is 0.2.
What is the maximum speed in kmph of the car
for safe driving ? (g = 10ms-2)
1) 21.6 kmph 2) 18.5 kmph
3) 25.4 kmph 4) 28.6 kmph​

Answer 1

Answer:

1) 21.6 kmph

Explanation:

In this question , one must observe the conversion units while solving!!!!

Answer 2

Answer:

Maximum speed of car is 21.6kmph

Explanation:

Given the radius of curved path of radius, $r=18m$

coefficient of friction,  $\mu=0.2$

and acceleration due to gravity, $g=10m/s^{2}$

To drive around a curved path without skidding, frictional force must be equal to centripetal force

             $\implies \mu mg=\frac{mv^{2} }{r}\implies \mu g=\frac{v^{2} }{r}$

                                         $\implies 0.2\times 10=\frac{v^{2} }{18}$

                                         $\implies v^{2}=36\implies v=6m/s$

speed in kmph, $v=6\times \frac{18}{5} =21.6km/h$