A uniform steel rod has mass 0.400 kg and length 50.0 cm and is horizontal. A uniform sphere with radius
10.00 cm and mass 0.800 kg is welded to one end of the bar, and a uniform sphere with radius 5.00 cm
and mass 0.200 kg is welded to the other end of the bar. The centers of the rod and of each sphere all lie
along a horizontal line. How far is the center of gravity of the combined object from the center of the rod?

Which car has the most kinetic energy? a. a car of mass 1000 kg with a speed of 3 m/s b. a car of mass 2000 kg with speed 7 m/s c. a car of mass 1000 kg with speed 7 m/s d. a car of mass 2000 kg with speed 3 m/s

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.

Hydrogen and helium are both members of?