Question

A curve on a flat road has curvature radius 111 m, and a caution sign urges drivers to slow to 60 km/h before negotiating the curve.Find the minimum frictional coefficient safe for driving at this speed along the curve of the road.

Answer 1

$$Ma= (mv^2)/R$$

$$F_s=mgk$$

$$(mv^2)/R=mgk$$

$$k= (mv^2)/mgR$$

$$60 km/h=600/36 m/s=50/3 m/s$$

$$k= v^2/gR$$

$$k= 〖50〗^2/(3^2∙9,8∙111)≈0,26$$

Ansver: 0,26