7. a roller coaster’s velocity at the top of a hill is 10 m/s. two seconds later it reaches the bottom ofthe hill with a velocity of 26 m/s. what was the acceleration of the coaster? 8. a roller coaster is moving at 25 m/s at the bottom of a hill. three seconds later it reaches the top ofthe hill moving at 10 m/s. what was the acceleration of the coaster? 9. a car traveling at 15 m/s starts to decelerate steadily. it comes to a complete stop in 10 seconds. what is it’s acceleration? 10. a child drops a ball from a window. the ball strikes the ground in 3.0 seconds. what is thevelocity of the ball the instant before it hits the ground?