Two cars collide head-on on a level friction-free road. the collision was completely inelastic and both cars quickly came to rest during the collision. what is true about the velocity of this system's center of mass? select one: a. it was never zero. b. it was always zero. c. it was not zero, but ended up zero. d. none of the above.

Akg a of 55 m at an of 11 ? . if is at 98 km/h, be ?

Blank liquids and gases exert a buoyant force on objects placed in them

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.