What is the difference between a mineral and a rock

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

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