Highly selective Backlog Qs for JEE MainPhysicsLaws of Motion
A car is negotiating a curved road of radius R . The road is banked at an angle θ . The coefficient of friction between the tyres of the car and the road is μ s . The maximum safe velocity on this road is:
Options
- Ag R 2 μ s + tan θ 1 - μ s tan θ
- Bg R μ s + tan θ 1 - μ s tan θ
- Cg R μ s + tan θ 1 - μ s tan θ
- Dg R 2 μ s + t a n θ 1 - μ s tan θ
Correct answer
B. g R μ s + tan θ 1 - μ s tan θ
Step-by-step solution
N = m g cos θ + m v 2 R sin θ f max = μ N ⇒ f m a x = μ s m g cos θ + μ s m v 2 R sin θ mg sin θ + f max = m v 2 R cos θ m g sin θ + μ s m g cos θ + μ s m v 2 R sin θ = m v 2 R cos θ g sin θ + μ s g cos θ = v 2 R cos θ - μ s sin θ g R tan θ + μ s 1 - μ s tan θ = v 2