can you help me with this question?
2016-02-27 3:18 pm
An ant crawls in a straight line at a constant speed of 0.24m/s, beginning in the corner of a square classroom, for 3.0m. It then turns exactly 90 degrees to the right, and proceeds an additional 4.0m with a constant speed of 0.44m/s, reaching the other corner of the same wall from which it began. What was the average speed for the full trip from corner to corner?
回答 (2)
2016-02-27 3:32 pm
Before turning 90° :
Distance crawls = 3.0 m
Time taken = (3.0 m) ÷ (0.24 m/s) = 25/2 s
After turning 90° :
Distance crawls = 4.0 m
Time taken = (4.0 m) / (0.44 m/s) = 100/11 s
Average speed for the full trip
= (Total distance) ÷ (Total time taken)
= (3.0 + 4.0 m) ÷ [(25/2) + (100/11) s]
= 7.0 ÷ [(275/22) + (200/22) m/s
= 7.0 ÷ (475/22) m/s
= 7.0 × (22/475) m/s
= 154/475 m/s
≈ 0.324 m/s
Distance crawls = 3.0 m
Time taken = (3.0 m) ÷ (0.24 m/s) = 25/2 s
After turning 90° :
Distance crawls = 4.0 m
Time taken = (4.0 m) / (0.44 m/s) = 100/11 s
Average speed for the full trip
= (Total distance) ÷ (Total time taken)
= (3.0 + 4.0 m) ÷ [(25/2) + (100/11) s]
= 7.0 ÷ [(275/22) + (200/22) m/s
= 7.0 ÷ (475/22) m/s
= 7.0 × (22/475) m/s
= 154/475 m/s
≈ 0.324 m/s
2016-02-27 3:31 pm
Ant travels a total distance = 3.0 + 4.0 = 7.0 m
Ant takes a total time = [3.0/0.24] + [4.0/0.44] = 12.5 + 9.09 = 21.6 s
Avg speed of ant = 7.0/21.6 = 0.32 m/s ANS
Ant takes a total time = [3.0/0.24] + [4.0/0.44] = 12.5 + 9.09 = 21.6 s
Avg speed of ant = 7.0/21.6 = 0.32 m/s ANS
收錄日期: 2021-04-18 14:31:28
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160227071805AAkZGRY