Which of the following describe an electric motor? Check all that apply.
A. Uses the interaction between a spinning coil of wire and a magnet
B. Can be powered by a hand crank
c. Changes mechanical energy to electrical enggy
D. Is found in many appliances with moving parts, like a vacuum
cleaner or a blender

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?

Bahan yang digunakan mencegah terjadinya polarisasi pada batu baterai a.larutan h2so4b.mncl2 dan serbuk karbonc.pbso4d.nh4cl

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light