The electric field just above the surface of the earth has been measured to be 139 N/C downward. What total charge (sign and magnitude) on the Earth is implied by this measurement

You have been called to testify as an expert witness in a trial involving a head-on collision. car a weighs 1515 lb and was traveling eastward. car b weighs 1125 lb and was traveling westward at 44.0 mph. the cars locked bumpers and slid eastward with their wheels locked for 22.5 ft before stopping. you have measured the coefficient of kinetic friction between the tires and the pavement to be 0.750 . how fast (in miles per hour) was car a traveling just before the collision? (this problem uses english units because they would be used in a u.s. legal proceeding.)

Why are graphs useful when interpreting data

Looking at this barometer, is the air pressure high or low? what type of weather would you expect? high, bad low, bad high, good low, good