Posts Tagged ‘web2.0’

Out Ankle Platform

March 30th, 2010 No comments

Out Ankle Platform

A bungee cord is 30.0 ( rm m) long when stretched a distance x, exerts a restoring force of magnitude kx. Your father-in-law (weight 99.0 kg) stands on a platform 45.0 m ( rm) from the ground and one end of the cable is firmly attached to the ankle and the other end to the platform. You have promised him that when you lower the platform will fall a distance of only 41.0 ( rm m) before the cable prevents it. You had to select several bungee cords, and tested by stretching it out, tying one end to a tree, and pulling the other end with a force of 410 N. In doing so, how far the bungee cord to be selected have been stretched? The answer is x = 0.624 m

k = F / x = mg / X = 99.0kg * 9.8ms ^ -2 / (41.0m – 30.0M) = ^ -1 88.2Nm And chuck: x = F / k = 410N / 88.2Nm ^ -1 = 4.65m (3 feet square )