Uma wants to recreate the discovery of superconductivity. Which describes the materials needed? A) a tool to increase temperatures, copper, resistance, a tool to measure electric current
B) a tool to drop temperatures, mercury, an electric current, and a tool to measure resistance
C) a tool to drop temperatures, mercury, resistance, a tool to measure electric current
D) a tool to increase temperatures, copper, an electric current, and a tool to measure resistance

Mass (kg) force (n) 5 25 10 50 15 75 20 100 a student was trying to find the relationship between mass and force. he placed four different masses on a table and pulled them using a spring scale. the table shows the different masses used in the experiment and the force required to pull each mass. the student concluded that more force was required to pull heavier objects. what comment would you make regarding his conclusion? a) no clear relation can be observed between mass and force from the data. b) there is a direct proportion between the mass and force listed in the table. c) gravity should have been taken into account while performing the experiment. d) there is an inverse proportion between the mass and force listed in the table.

Uppose we consider the system of the three capacitors as a single "equivalent" capacitor. given the charges of the three individual capacitors calculated in the previous part, find the total charge qtot for this equivalent capacitor. express your answer in terms of v and c.

How much energy must a refrigerator absorb from 225 g of water so that the temperature of the water will drop from 35°c to 5°c