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At a certain time when a and B are competing on a straight road, B is at L1 = 11m in front of a, and B's speed v b = 600m. If a is doing well, B will be able to do well Acceleration, acceleration a = 2m / S ^ 2, B car speed unchanged, regardless of car length (1) After how long, the distance between workshop a and workshop B is the largest, and what is the maximum distance? (2) Can car a overtake car B at the terminal? Urgent. Can we solve it today? The speed of vehicle B is 60m / s, and that of vehicle a is 50M / s. at this time, vehicle B is still 600m away from the finish line Why is the distance the largest at the same speed
When t = 0, the speed of car B is higher than that of car a, and car B is in front of car a at this time. So you can imagine that the distance of car B is more than that of car a every second. Therefore, as long as the speed of car B is faster than that of car a, the distance between them will continue to increase. When the two speeds are equal, the distance reaches the maximum, and then car a will be faster than car B, It's equivalent to catching up a little distance every second, so the distance between them will decrease again. Do you understand~
(1) T1 = (V B-V a) / a = 5S; Smax = s B 1-s a 1 + L1 = v b * T1 - (V a T1 + 1 / 2 * a * T1 ^ 2) + 11m = 36m
(2) When t = T2, car a just exceeds car B
S A2 = V A2 + 1 / 2 * a A2 * T2 ^ 2 = 50t2 + T2 ^ 2
S B 2 = v b T2 = 60t2
In this case, s A2 = s B2 + L1
It can be solved that T2 = 11S
At this point, S B 2 = 660m > L 2 = 600m, so car a can't exceed car B at the end
If you don't understand, you can ask me again
A, B and C are passing a road sign at the same speed on a straight road. From this point on, car a is moving in a straight line at a constant speed. Car B is moving in a straight line at a constant acceleration and then in a straight line at a constant deceleration. Car C is moving in a straight line at a constant deceleration and then in a straight line at a constant acceleration. When they pass the next road sign at the same speed, then ()
A. Car a goes through the next road sign first B. car B goes through the next road sign first C. car C goes through the next road sign first D. three cars go through the next road sign at the same time
Because B accelerates first and then decelerates, its average speed in the whole movement process is larger than that of A. after the same displacement, its time must be smaller than that of a moving at a constant speed. However, B decelerates first and then accelerates, its average speed in the whole movement process is smaller than that of a, so its time in the same displacement is larger than that of A; Therefore, B will be the first to reach the next signpost, and C will be the last to reach the next signpost
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