The electric field near the surface of earth points downward and has a magnitude of 160 n/c (a) compare the upward electric force on an electron with the downward gravitational force 2.8e12 . the electric force is is much larger. o both forces are equal. o the gravitational force is is much larger x (upward force/ downward force) (b) what magnitude charge should be placed on a penny of mass 6 g so that the electric force balances the weight of the penny near earth's surface?

If a clock aboard a space ship traveling at 0.900 c of the speed of light relative to earth chimes once at the beginning of the hour and again when it reads one hour later, how much time would an observer on earth say elapsed between the two chimes?

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.