Which of the following statements are correct regarding electric field lines and equipotential lines? (select all that apply.)
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a)the electric field at a point cannot be in two different directions and therefore two field lines can never cross.

b) if equipotential lines of different potentials cross that would imply that the potential at that point has two different values and that is possible under certain special conditions.

c) if equipotential lines of different potentials cross that would imply that the potential at that point is zero.

d) the electric field at a point cannot be in two different directions but that does not prevent two field lines from crossing.

e)if equipotential lines of different potentials cross that would imply that the potential at that point has two different values and that is not physically possible.

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

A100 kg running back runs at 5m/s into a stationary linebacker. it takes 0.5 for the running back to be completely stopped

Which body is in equilibrium? (1) a satellite orbiting earth in a circular orbit (2) a ball falling freely toward the surface of earth (3) a car moving with a constant speed along a straight, level road (4) a projectile at the highest point in its trajectory