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Question 7 Question 8 (5 points) In a perfectly elastic collision, (5 points) Which of the below indicates that the momentum and kinetic energy of both colliding collision is elastic? objects: O a. Become zero O a. Both objects get stuck together after O b. Remain the same collision O c. Decrease O b. Objects are hotter after collision O d. Increase O C. Objects are deformed after collision Question 9 Question 10 (5 points) A 1000-kg car traveling initially with a (5 points) A 2200 kg car traveling at 30 m/s speed of 20 m/s in an eastern direction crashes collides with another 2200 kg car that is at rest. into the rear end of 2000-kg truck moving in the The two bumpers lock and the cars move forward same direction with a speed of 10 m/s. The together. What is their final velocity? velocity of the car right after the collision is 15 m/s to the east. What is the velocity of the truck after the collision? O a. 10 m/s O a. 7.5 m/s O b. 15 m/s O b. 12.5 m/s O c. 30 m/s O c. 2.5 m/s O d. 0m/s O d. 0m/s