Which one of the following is a proper unit for speed?

a. seconds
b. meters
c. meters per second
d. meters per second per second

Why is alternating current more effective at long–distance travel than direct current? a. the power lines are made out of conductors. b. transformers increase or decrease voltage as needed. c. the ac generator is more efficient. d. ac has lower voltage than dc.

F500 j of energy were added to 1 kg of each of these samples, which would experience the least temperature increase?

Phase changes are chemical changes. true or false