Three-phase, 4-wire panelboards are usually constructed with an even number ofspaces available for each phase; thus, the total number of spaces would be in incre-ments of 6, such as 12, 18, 24, 30, 36, or 42. how many spaces would be available forthe later addition of circuit breakers in panelboard p-1 after the panelboard has been equipped as scheduled?

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

The force it would take to accelerate an 900-kg car at the rate of 6m/s2