a crate of grapes lifted 10 meters gains 200 j of potential energy. if the same crate is instead lifted 20 meters, its gain in potential energy is

A3.9 g aluminum foil ball with a charge of +4.1×10−9 c is suspended on a string in a uniform horizontal e⃗ field. the string deviates to the right and makes an angle of 30∘ with the vertical. part a part complete what information about the e⃗ field can you determine for this situation? what information about the field can you determine for this situation? only the magnitude of e⃗ only the direction of e⃗ both the magnitude and the direction of e⃗ none of the above previous answers correct part b determine the magnitude of the electric field. express your answer with the appropriate units. e e = nothing nothing request answer part c determine the direction of the electric field. determine the direction of the electric field. to the right to the left away from you toward you

Consider each of the electric- and magnetic-field orientations given next. in each case, what is the direction of propagation of the wave? a)\vec ein the +xdirection,\vec bin the +ydirection. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction b)\vec ein the -y direction,\vec bin the +x choose+ x direction- x direction+ y direction- y direction+ z direction- z direction c)\vec ein the +z direction,\vec bin the -x direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction d)\vec ein the +y direction,\vec bin the -z direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction

No matter what energy transformation we discuss, we know that no energy transfer is 100% efficient. you are about to enter a bicycle rave. you have trained extensively and eaten well to maximize your energy input throughout the bicycle race. you know that some of your kinetic energy will become wasted energy in the form of heat. what is the source of the heat energy and how can you minimize it to maximize the efficiency of your performance in the race? a) you are the source of the heat energy. you can minimize the heat energy but selecting the appropriate clothes to wear. b) air resistance is the source of he heat energy. you can minimize the air resistance by your position while riding the bicycle. c) friction is the source of the heat energy. you can minimize the friction by lubricating all appropriate parts and keeping the tires well inflated. d) kinetic energy is the source of the heat energy. you can reduce the production of heat energy but minimizing the energy you expend to race on the bicycle.