Q. The burning of gasoline in a car releases about 3.0 × 10^4 kcal/gal. If a car averages 43 km/gal when driving 90 km/h, which requires 20 hp, what is the efficiency of the engine under those conditions?
Q. Suppose an electric field with a magnitude of 2.8 E 4 N/C at a certain location, points due south. If a charge of -4.0 E -6 C is brought to the location, what is the electrostatic force that acts on this charge?