Average Acceleration?

Average acceleration?

• 2.11.6 (2.00) The driver of a jet-propelled car is hoping to break the world record for ground-based travel of 341 m/s. The car goes from rest to its top speed in 26.5 seconds, undergoing an average acceleration of 13.0 m/s2. Upon reaching the top speed, the driver immediately puts on the brakes, causing an average acceleration of −5.00 m/s2, until the car comes to a stop. (a) What is the car's top speed? (b) How long will the car be in motion?

• Answer:

  a) When accelerating from rest: speed = acceleration × time They give you the acceleration. They give you the time. Multiply. b) When decelerating to a stop: time = initial speed / deceleration You figured out the "initial speed" in part (a). They give you the deceleration. Divide.