In a bicycle race on a straight road, the leader is 72.0 m from the finish line and continues to travel to the finish line with
a constant speed of 12 m/s. When the leader is 72.0 m from the finish line, the second-place rider is 5.0 m behind him and traveling with a speed of 11.0 m/s when she decides to accelerate, keeping a constant acceleration for the rest of the race. The two riders end up crossing the finish line at exactly the same time.(a) Calculate the value of the second rider?s constant acceleration that allows her to cross the finish line at exactly the same time as the first rider.m/s2(b) What is the speed of the second rider as she crosses the finish line?m/s(c) What is the second rider's average speed over the final 77 m of the race?m/s
1 answer:
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Answer:
41.16 Joules
Explanation:
Potential energy at a given instant is a function of mass and height of an object. The formula is
(a) The plastic rod has a length of L=1.3m. If we divide by 8, we get the length of each piece:
(b) The center of the rod is located at x=0. This means we have 4 pieces of the rod on the negative side of x-axis, and 4 pieces on the positive side. So, starting from x=0 and going towards positive direction, we have: piece 5, piece 6, piece 7 and piece 8. Each piece is 0.1625 m long. Therefore, the center of piece 5 is at 0.1625m/2=0.0812 m. And the center of piece 6 will be shifted by 0.1625m with respect to this:
(c) The total charge is
. To get the charge on each piece, we should divide this value by 8, the number of pieces:
(d) We have to calculate the electric field at x=0.7 generated by piece 6. The charge on piece 6 is the value calculated at point (c):
If we approximate piece 6 as a single charge, the electric field is given by
where
and d is the distance between the charge (center of piece 6, located at 0.2437m) and point a (located at x=0.7m). Therefore we have
poiting towards the center of piece 6, since the charge is negative.
(e) missing details on this question.
(b) The center of the rod is located at x=0. This means we have 4 pieces of the rod on the negative side of x-axis, and 4 pieces on the positive side. So, starting from x=0 and going towards positive direction, we have: piece 5, piece 6, piece 7 and piece 8. Each piece is 0.1625 m long. Therefore, the center of piece 5 is at 0.1625m/2=0.0812 m. And the center of piece 6 will be shifted by 0.1625m with respect to this:
(c) The total charge is
(d) We have to calculate the electric field at x=0.7 generated by piece 6. The charge on piece 6 is the value calculated at point (c):
If we approximate piece 6 as a single charge, the electric field is given by
where
poiting towards the center of piece 6, since the charge is negative.
(e) missing details on this question.