m Question 4 0X 10 pts A small sphere of mass 2 kg is attached to the end of a cord of length 1 m and rotated in a vertical circle about a xed point 0. Determine the tension in the cord at the uppermost point of the trajectory if the speed at this point is 10 m/s. Use g=9.8 m/sz. Report your answer as a positive number in newtons. 160.8 Try again. The tension is less at the top of the circle. The centripetal acceleration needed is provided by Fg and tension so the sum ofT and Fg is equal to the net (centripetal) force. m Question 1 0/ 10 pts A coin is placed on a large disk which rotates uniformly at a rate of 3 rotfs. The coefcient of friction between the coin and the disk is 0.1. What is the maximum distance from the center of the disk that the coin could be placed without slipping? Report your answer in meters. 0.0519 Try again. The net force (centripetal) needed must be less than or equal to the frictional force. Friction can be represented with umg while the centripetal force can be represented with mv"2fr. Since the velocity is given in rotations per second, consider that this is one complete circumference per second (v=2nr/t). Substitute for velocity in the centripetal equation and then set equal to the friction. Notice that mass cancels so it is not needed