Tristan is an engineer working on a design for a new roller coaster. He wants the car to shoot out of the station very fast but needs a superconductor to be able to accomplish this. He is looking at different materials to use on the tracks
of the roller coaster. What is necessary for his material to function as a superconductor? Check all that apply.
OT O a solid metal
O conductivity
O a very cold temperature
a low boiling point
O no resistance

Asuppose a suitcase has a mass of (m) 30 kg and a net force (n) of 10 kg*m/s. what is the acceleration rate of the suitcasein m/s? show your work to support your answer.

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)