Question

The coefficient of friction between the tyres and road is 0.25. The maximum speed with which a car can be driven round a curve of radius 40 m without
sliding (g= 10 ms-2)
5 ms -1
10 ms -1
15 ms -1
18 ms -1​

Answer 1

Given :

Coefficient of friction = 0.25

Radius of curvature = 40m

To Find :

The maximum safe speed with which the car can be driven$.$

Solution :

❖ A vehicle taking a circular turn on a level road. If μ is the coefficient of friction between tyres and road, then the maximum velocity with which the vehicle can safely take a circular turn at radius r is given by, v = √μrg

• v denotes safe speed
• μ denotes coefficient of friction
• r denotes radius of circular path
• g denotes acceleration

By substituting the given values;

➙ v = √μrg

➙ v = √0.25 × 40 × 10

➙ v = √100

➙ v = 10 m/s

∴ (B) is the correct answer!

❖ Knowledge BoosteR :

• For frictional force relative motion between two bodies or surfaces is not necessary. In fact, contact between two bodies or surfaces is necessary.
• The limiting frictional force between two surfaces in contact with each other depends only on μ (nature of surfaces) and normal contact force R. It does not depend on their shape, size or surface area.