Energy that comes from moving objects or objects that have stored energy

Acylindrical specimen of a nickel alloy having an elastic modulus of 207 gpa (30 × 106psi) and an original diameter of 10.2 mm (0.40 in.) experiences only elastic deformation when a tensile load of 8900 n (2000 lbf) is applied. compute the maximum length of the specimen before deformation if the maximum allowable elongation is 0.25 mm (0.010 in.)

Compare the horizontal displacement of the two balls as they travel to the ground. what do you observe?

What is the single most important equation in all of physics?