Have a cubical box (sides all of length a) made of 6 metal plates which are insulated from each other. The left wall is located at y=-a/2,the right wall is at y=+a/2. Both left and right walls are held at constant potential V=V0. All four other walls are grounded. (Note that I've set up the geometry so the cube runs from x=0 to x=a, and from z=0 to z=a, but from y=-a/2 to y=+a/2 This should actually make the math work out a little easier!) Find the potential V(x, y,z) everywhere inside the box. Do your formulas give V=0 at the center of this cube? Is E=0 there? (Should they be??)

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

If state law mandates that elevators cannot accelerate more than 2.40 m/s2 or travel faster than 14.8 m/s , what is the minimum time in which an elevator can travel the 373 m from the ground floor to the observatory floor? ?

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.