Stage Problem 1 (Driving in traffic)
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A car accelerates from rest up to 30 m/s for 4s.
It drives at a constant velocity for 15 s.
Then the driver sees a red light and hits the brakes, coming to a complete stop with an acceleration of -5 m/s2.
1) The acceleration in stage 1.
2) The time in stage 3.
3) The distance traveled in each stage.
4) The total time of travel (for all three stages added up)
5) Complete this sentence: The initial velocity of Stage 2 is always the same as the _______________________ velocity of Stage 1.
Stage Problem 2 (Tree in the road)
Tom is driving his Prius at a speed of 20 m/s. He sees a fallen tree in the road 40 m ahead.
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He travels at CV for 1 second while analyzing the situation
He hits the brakes, which create an acceleration of -4 m/s2.
a) How far does he go during the CV analyzing phase?
b) How far does he go while braking (braking distance)?
c) What is the car’s total distance of travel (both analyzing AND braking)?
d) How long does it take to stop the car (both analyzing and braking)?
e) Will he hit the tree, or stop before hitting it?
Stage Problem #3 (Alex leaving school)
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Alex is still in the East parking lot for 10 seconds.
He speeds up from rest, covering a distance of 30 meters in a time of 6s.
He drives at a constant velocity for 20 seconds.
He slows down to a complete stop in 4 seconds.
He is still for another 10 seconds.
a) What is his acceleration during stage 2 (speeding up)?
b) What is his final velocity at the end of stage 2 (speeding up)?
c) What is his acceleration during stage 4 (slowing down)?
d) How far did he travel in each stage?
e) How long did the entire trip take?
What was his average speed for the entire trip?