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Entering the Freeway. A car sits in an entranceramp to a freeway, waiting for a

ID: 1758484 • Letter: E

Question

Entering the Freeway. A car sits in an entranceramp to a freeway, waiting for a break in the traffic. The driveraccelerates with constant acceleration along the ramp and onto thefreeway. The car starts from rest, moves in a straight line, andhas a speed of 35 m/s (78 mi/h) when it reaches the end of the95 m long ramp. (a) What is the acceleration of the car?
  ? m/s2

(b) How much time does it take the car to travel the length of theramp?
   ? s

(c) The traffic on the freeway is moving at a constant speed of35 m/s. What distance does the traffictravel while the car is moving the length of the ramp?
? m
(a) What is the acceleration of the car?
  ? m/s2

(b) How much time does it take the car to travel the length of theramp?
   ? s

(c) The traffic on the freeway is moving at a constant speed of35 m/s. What distance does the traffictravel while the car is moving the length of the ramp?
? m

Explanation / Answer

(a) use    v2 = 2ad .       352 = 2 * a *95 .           a =   6.45m/s2 . (b) use    v = at .         35 = 6.45 * t .          t = 5.43seconds . (c) use   d = speed * time =  35 * 5.43 =    190meters . (b) use    v = at .         35 = 6.45 * t .          t = 5.43seconds . (c) use   d = speed * time =  35 * 5.43 =    190meters