Question

A car moves at a constant speed on a road as shown in figure. The normal force by the road on the car is $N_{A}$ and $N_{B}$ when it is at the points $A$ and $B$ respectively

• A. $N_{A}=N_{B}$
• B. $N_{A} >\,N_{B}$
• C. $N_{A} <\,N_{B}$
• D. Insufficient information to decide the relation of $N_{A}$ an $N_{B}$

Answer 1

Answer: (C)

Both $A$ and $B$ are convex upward
$\Rightarrow mg-N=\frac{m v^{2}}{R}$
$\Rightarrow N=m g-\frac{m v^{2}}{R}$
As $R_{A}<\,R_{B}, \frac{m v^{2}}{R_{A}} >\,\frac{m v^{2}}{R_{B}}$
$\frac{-m v^{2}}{R_{A}}<\,\frac{-m v^{2}}{R_{B}}$
$mg-\frac{m v^{2}}{R_{A}}<\,mg-\frac{m v^{2}}{R_{B}}$
$\Rightarrow N_{A}<\, N_{B}$