A RED toy car of mass 4.7 kg, hits BLUE toy car, with mass 1.2 kg, head-on. The blue car originally had a velocity of -15 m/s. After the two cars collide, they stick together and stop. What was the Red car's original velocity?

Arocket starts from rest and moves upward from the surface of the earth. for the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 12.80 m/s32t, where the +y-direction is upward. (a) what is the height of the rocket above the surface of the earth at t = 10.0 s? b) what is the speed of the rocket when it is 325 m above the surface of the earth?