circular motion f6

☆ 天與空 ★ ◤

2009-10-21 5:57 am

1. A car of mass 800kg moves with a uniform speed of 15 ms-1 in a ircular path of radius 100m on a horizontal surface.

(i) What are the magnitude and direction of the centripetal force acting on the car?

(ii) How is this centripetal force produced?

2. By considering the forces acting on a car when it moves around a curve, explain , with the aid of a diagram , why roads are banked at corners.

really thz~~

回答 (1)

天同

2009-10-21 6:42 am

✔ 最佳答案

1. (i) Centripetal force = 800 x 15^2/100 N
The force is pointing towards the centre of the circular path
(ii) It is produced from friction between the tyres and road surface.

2. When the curved road is banked, the normal reaction on the car will be inclined at an angle to the vertical. As such, there is a horizontal component of the normal reaction pointing towards the centre of the circular path. This component would provide the necessary centripetal force for the car to turn round the corner, thus reducing the friction on the tyres. Therefore, the car could turn at a higher speed without slipping.

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