I. A hump back bridge has a radius of curvature of 40m. Calculate the max speed at which a car could travel across the bridge without leaving the road at the top of the hump. I realised that weight - contact force at the top would give the resultant centripetal force. But i have no equation for the contact force. II. Calculate the speed at which a plane must be flying when looping-the-loop of radius 0.80 km so that the pilot feels no force from eitherhis harness or his seat. component of weight towards the centre - contact force = resultant centripetal force Here again i have no equation for the contact force. I'm wondering if i should be putting the conatct force to zero??