BackA robot used in a pharmacy picks up a medicine bottle at t = 0. It accelerates at 0.20 m/s² for 4.5 s, then travels without acceleration for 68 s and finally decelerates at ―0.40 m/s² for 2.5 s to reach the counter where the pharmacist will take the medicine from the robot. From how far away did the robot fetch the medicine?
Determine the stopping distances for an automobile going a constant initial speed of 95 km/h in the +𝓍 direction, and human reaction time of 0.40 s:
(a) for an acceleration a = ― 2.5 m/s²"
(I) A car slows down from 28 m/s to rest in 6.3 s. What was its (constant) acceleration?
A world-class sprinter can reach a top speed (of about 11.5 m/s) in the first 18.0 m of a race. What is the average acceleration of this sprinter and how long does it take her to reach that speed?
"Consider the street pattern shown in Fig. 2–51. Each intersection has a traffic signal, and the speed limit is 40 km/h. Suppose you are driving from the west at the speed limit. When you are 10.0 m from the first intersection, all the lights turn green. The lights are green for 13.0 s each.
(b) Another car was stopped at the first light when all the lights turned green. It can accelerate at the rate of 2.00 m/s² to the speed limit. Can the second car make it through all three lights without stopping? By how many seconds would it make it, or not make it?
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Show that v = (v + v₀)/2 (see Eq. 2–12d) is not valid when the acceleration a = A + Bt, where A and B are non-zero constants.