Question

You are observing the poles along the side of the road. You have already stopped and measured the distance between adjacent poles as 41.1 m. You are now driving again and have activated your smartphone stopwatch. You start the stopwatch at t = 0 as you pass pole #1. At pole #2, the stopwatch reads 10.3 s. At pole #3, the stopwatch reads 26.8 s. Your friend tells you that he was pressing the brake and slowing down the car uniformly during the entire time interval from pole #1 to pole #3. (Assume you are driving in the positive direction when t = 0.)

(a)

What was the acceleration (in m/s2) of the car between poles #1 and #3? (Indicate the direction with the sign of your answer.)

(b)

What was the velocity (in m/s) of the car at pole #1? (Indicate the direction with the sign of your answer.)

(c)

If the motion of the car continues as described, what is the number of the last pole passed before the car comes to rest?

Answer 1