Is a compound considered a pure substance?

True or false: the cycle of seasons on the earth is caused by the tilt of the earth on its axis toward and away from the sun.

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.