Question

Three identical cars A, B and C are moving at the same speed on three bridges. The car A goes on a place bridge, B on a bridge convex upward and C goes on a bridge concave upward. Let F_A, F_B and F_C be the normal forces exerted by the car on the bridges when they are at the middle of bridges. 

Options

• F_A is maximum of the three forces. 

• F_B is maximum of the three forces. 

• F_C is maximum of the three forces. 

• F_A = F_B = F_C. 

Answer 1

F_C is maximum of the three forces. 

At the middle of bridge, normal force can be given as : \[\text{N}_\text{A} = \text{mg}\]

\[\text{N}_\text{B} = \frac{\text{mv}^2}{\text{r}} - \text{mg}\]

\[ \text{N}_\text{C} = \frac{\text{mv}^2}{\text{r}} + \text{mg}\]

So, F_C is maximum.