A 70.0 kg stuntman stands on a bridge. He is attached to a bungee cord with an unstretched length of 15.0 m. The bungee cord has a spring constant of 71.8 N/m and is attached to the bridge at the level of his feet. He jumps off the bridge, and the bungee cord extends to 44.0 m. What is the potential energy stored in the cord? How did the stuntman’s gravitational potential energy change?

A pogo stick has a spring with a force constant of 2.50×10^4N/m, which can be compressed 12.0 cm. To what maximum height can a child jump on the stick using only the energy in the spring, if the child and stick have a total mass of 40.0 kg? Explicitly show how you follow the steps

A horizontal spring with a spring constant k = 126 kN/m is relaxed from an extension x = 9.3 cm back to its unstretched length. Calculate the change in potential energy in Joules to 2 s.f. Your Answer: Answer

A new event has been proposed for the next Winter Olympics. As seen in the figure below, an athlete will sprint 100 m, starting from rest, then leap on a 25.0 kg bobsled. The person and bobsled will then slide down a 50.0 m long ice-covered (frictionless) ramp, sloped at 20.0°, and into a spring with a carefully calibrated spring constant of 2000.0 N/m. The athlete who compresses the spring the farthest wins the gold medal. Lisa, whose mass is 40.0 kg, has been training for this event. She can reach a maximum speed of 12.0 m/s in the 100 m dash. How far will Lisa compress the spring? 20°