A bungee jumper of mass m jumps off a bridge. Assume that the bungee cord behaves like am ideal spring of spring constant k. When the jumper is at the lowest point in the motion that follows, the extension of the bungee cord is x.
After reaching the lowest point for the first time, the jumper rebounds straight upwards.
What is the magnitude of her velocity at the instant that the cord is at its natural length?

a) √(k/m) x
b)√[(kx²/m) - 2gx]
c) √(2gx)
d) √(-2gx)
e) None of the above

Scout feels ill one day before school. her mother puts a thermometer in her mouth and the temperature begins to climb to 100°f. what is happening between the cooler thermometer and scout's body? a) scout's body is applying a force to the particles in the thermometer. b) kinetic energy is being transferred from her mouth to the thermometer. c) potential energy is being lost by the thermometer and gained by scout's body. d) the potential energy stored in foods is converted to mechanical energy to raise the mercury in the thermometer.