Question

A car of mass m is crossing the convex bridge of radius of curvature R with speed V. At the highest point the thrust is (\(g\) = gravitational acceleration)

• A. \(mg\)
• B. \(\frac{mv^2}{R}\)
• C. \(mg-\frac{mv^2}{R}\)
• D. \(mg+\frac{mv^2}{R}\)

Hint:

At the top, weight minus normal reaction provides the centripetal force.

Answer 1

The Correct Option is C

Step 1: Forces
Down: $mg$. Up: $N$. Direction to the centre: down.

Step 2: Equation
Net inward force $= mg - N = mV^2/R$.

Step 3: Result
$N = mg - mV^2/R$. Option (C).

Final Answer:
Option (C). \[ \boxed{mg - \frac{mV^2}{R}} \]