physics hw

Homework 7 PS 115L

Name:___________________________

Lab Partners:____________________, ____________________,____________________

1. Answer the following questions: x What was the total work done in your adiabatic compression?

x What makes a process adiabatic?

x How much energy did your cube release after being heated up?

x If I were to increase the mass of your cube 10 times and the final temperature of the cube was the same. How much more energy would it have released?

2. True or False: x If a gas undergoes an adiabatic compression, pressure will increase but temperature will

decrease. – True False x Heat transfer is maximum in adiabatic processes. – True False x Motor efficiency has to always be above 100% – True False x Heat transfer only occurs in one direction. – True False x The mass of an object factors in how much energy it is required to increase/decrease

temperature– True False 3. A 1 kilogram packet of Nitrogen on the surface of Earth (pressure of 101,330 Pa and

temperature of 293 K) is forced to an altitude of 10 km by an aircraft, where the temperature is - 55 ºC and the pressure is 23,910 Pa. What is the new volume of the packet of Nitrogen? (R = 8.314 J/mol/K)

Homework 7 PS 115L

4. Kenny is dropped into a volcano. Stan and Kyle try to use a lift to save Kenny from rising lava. The efficiency of the motor is 0.4 and Kenny has a weight of 40kg. In order to save him, they must lift him 50 meters in 15 seconds. The voltage going into the motor is 200 V and the current is measured to be 1.25 A. Will the motor provide the necessary power to save Kenny or will he die? What is the fastest speed that the motor can lift Kenny?