Question

A fly-over bridge is a part of a vertical circle of radius $80m$ and a vehicle is travelling on it. The vehicle does not leave the surface of bridge at its highest point, if maximum speed of vehicle is:

• A. $14m/s$
• B. $21m/s$
• C. $28m/s$
• D. $42m/s$

Answer 1

Answer: (C)

$28m/s$

For the vehicle not to leave the surface, it has to travel with critical velocity.
So, $v=\sqrt{gR}$
$=\sqrt{9.8\times 80}$
$=\sqrt{784}$
or, $v=28m{s}^{-1}$