What is the frequency of a wave that has a wave speed of 80 m/s and a wavelength of 0.20 m?

How are the crust and the inner core alike? a) they are both solid. b) they both have the same temperature. c) they are both under the same pressure. d) they are both very close to the center of the earth.

What belongs in the areas marked x and y? x: the internal energy of a piston system increases as heat is added and rises to a cool area y: as thermal energy is added to a container, some of the energy is lost to the environment x: as thermal energy is added to a container, some of the energy is lost to the environment y: the internal energy of a piston system increases as heat is added and rises to a cool area x: a cold spoon placed in hot liquid gets warmer y: thermal energy is converted to light energy x: thermal energy is converted to light energy y: a cold spoon placed in hot liquid gets warmer

Aspring with an unstrained length of 0.071 m and a spring constant of 2.6 n/m hangs vertically downward from the ceiling. a uniform electric field directed vertically upward fills the region containing the spring. a sphere with a mass of 5.29 10-3 kg and a net charge of +7.2 µc is attached to the lower end of the spring. the spring is released slowly, until it reaches equilibrium. the equilibrium length of the spring is 0.058 m. what is the magnitude of the external electric field?