21. The figure below shows a student before and after a bungee jump. The bungee cord has an unstretched length of 200 m.
After
Before
Student
Bridge
Bungee
cord
20.0 m
Extended
bungee
cord
55.0 m
Lowest point
Stationary
student
River
The mass of the student is 50.0 kg.
The gravitational field strength is 9.8 N/kg.
(a) Write down the equation which links gravitational field strength, gravitational
potential energy, height and mass.

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

Jasmine is diving off a 3-meter springboard. her height in meters above the water when she is x meters horizontally from the end of the board is approximated by the equation h=-x^2+3x+3. what is the maximum height jasmine will reach on her dive?

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?