Which of the following is true about rocks?
a. rocks are composed of only one mineral.
b. rocks do not contain any nonmineral matter.
c. coal is not considered a true rock.
d. most rocks are a mixture of minerals.

Aparticle with mass 1.81×10−3 kg and a charge of 1.22×10−8 c has, at a given instant, a velocity v⃗ =(3.00×104m/s)j^. what are the magnitude and direction of the particle’s acceleration produced by a uniform magnetic field b⃗ =(1.63t)i^+(0.980t)j^?

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects