OK here goes.... I have a 20kg weight attached to a 10 meter long wire rope. The rope is fixed vertically to a cross beam. The rope has an elastic stretch limit of 47.5 kN/mm^2. If I lift the 20kg weight up 1 meter and then let it go what would the maximum force exerted by weight be on the wire rope? It's been a very very long time since I studied Newton so forgive me if I'm barking loudly up the wrong tree! I started of with Potential Energy = Mass X Gravity X Height but this didn't seem to cut the mustard so I then went for: Elastic Potential Energy = 1/2 x (k Spring Constant) x (L Spring Length)^2 But I'm not sure if this is the correct equation to use.... Impulse = (Mass x Velocity Initial) - (Mass x Velocity Final) Which again doesn't seem right but maybe I'm getting confused... Tension = Mass x Gravity x SQRT(2xHeight/Length Increase) So I have a selection of formulas that I think I should be using but I don't think I have the correct data to complete the formulas. So this is what I came up with but I don't really know if I'm going along the right lines or not. Velocity = sqrt 2 x9.81x1 = 4.429446918 m/s Potential Energy = 20x9.81x1 = 196.2 Joules Momentum = 20 x 4.429446918 = 88.58893836kg m /s Force = Change in Momentum / Time = 88.58893836 / 0.1 Second = 885.8893836 So just how far wide of the mark am I?