A circular road of radius r is banked for a speed v = 40 km/hr. A car of mass of m attempts to go on the circular road. The friction coefficient between the tyre and the road is negligible.

(a) The are cannot make a turn without skidding.

(b) If the car turns at a speed less than 40 km/hr, it will slip down.

(c) If the car turns at the car is equal to \[\frac{\text{mv}^2}{\text{r}}\]

(d) If the car turns at the correct speed of 40 km/hr, the force by the road on the car is greater than mg as well as greater than \[\frac{\text{mv}^2}{\text{r}}\]

#### Solution

(b) If the car turns at a speed less than 40 km/hr, it will slip down.

(d) If the car turns at the correct speed of 40 km/hr, the force by the road on the car is greater than mg as well as greater than \[\frac{\text{mv}^2}{\text{r}}\].

The friction is zero and the road is banked for a speed v = 40 km/hr. If the car turns at a speed less than 40 km/hr, it will slip down.