Science fair help needed! Horses use the energy stored in their tendons to help propel them over a jump- much like a spring. By determining the spring constant for the leg, the student wants to then calculate the potential energy stored in that leg. Would this work? From her research proposal: I will use the equation, PE=1/2kx² to find the potential energy the leg stores (where k=spring constant, x=spring displacement). X will be found by measuring the smallest distance between the two measuring points when the horse has both feet on the ground and subtracting from equilibrium. k can be solved for by using the equation; k= (x-x₁)/F. x being the displaced length, x₁ being leg at equilibrium and F equaling force. The values I will be using for that equation will be x equaling leg being stood on, x₁ relaxed leg, F being force on standing leg. To find force I will take the Weight of horse in kg then to find force on one leg, multiply by .55 (for forelimbs) or .45 (hindlimbs) then divide by two. Does this make sense? The difference (x) between a leg at rest and under weight is 0.025m, Force is 1225N so spring constant is 0.00002041? This makes for a very small value for PE too? I should include that I a biology teacher that is taking students to a state science fair. My background in physics is limited and the student is asking for help so I am seeking help on her behalf. Thank you!