Andrew fitted an electric toy car with hard rubber wheels that had deep treads a

游客2024-01-12  14

问题 Andrew fitted an electric toy car with hard rubber wheels that had deep treads and placed the car on a smooth, flat surface. Andrew started the car and a stopwatch at the same time. Andrew stopped the stopwatch as the car crossed the 75-foot mark. He calculated the results of 3 separate trials as shown in the table below.

Andrew repeated the procedure, except he fitted the car with soft rubber wheels that were smooth and lacked treads. The results are shown in the table below.
[br] Assuming the car in Procedure 1 traveled at a constant speed, approximately how long would it take the car to travel 100 feet?

选项 A、100 seconds
B、68.4 seconds
C、30.4 seconds
D、25 seconds
E、22.8 seconds

答案 C

解析 The correct answer is C. The first step is to calculate the average speed for all three trials:(22.8+23.2 + 22.5)+3 = 22.8. Next, since the car traveled at a constant speed, you can set up a proportion between the time and distance of the whole run and the time and distance of the partial run: 22.8÷75 = 0.304 sec/feet. Finally, multiply 0.304 by 100 to get 30.4 seconds.
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