The first electric generators used direct current, so they needed to be reversed manually on a regular basis in order to work pr
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find acceleration force divided by Mass
a=f/m
Answer:
It took Kevin 26 minutes to run from markers 1 to 4
His average speed from mile markers 1 to 4 is 0.154 miles/minute
Kevin must run by average speed 0.1 miles/minute to finish the race
Explanation:
Lets explain how to solve the problem
A half marathon 13.1 miles
Kevin took 8 minutes to run from mile marker 1 to mile marker 2 and
18 minutes to run from mile marker 2 to mile marker 4
→ He took 8 minutes and 18 minutes to run from marker 1 to marker 4
→ The total time of the first 4 marker = 8 + 18 = 26 minutes
<em>It took Kevin 26 minutes to run from markers 1 to 4</em>
<em></em>
Average speed is total distance divided by total time
The average speed of Kevin as he ran from mile marker 1 to mile
marker 4 is the 4 miles divides by 26 minutes
→ Average speed = 4 ÷ 26 = = 0.154 miles/minute
<em>His average speed from mile markers 1 to 4 is 0.154 miles/minute</em>
<em></em>
It took Kevin 71 minutes to pass mile marker 9
Kevin need to complete the race in 112 minutes, then what must
Kevin's average speed be as he travels from mile marker 9 to the
finish line?
The total distance of the race is 13.1 miles, he ran 9 miles
→ The remaining distance = 13.1 - 9 = 4.1 miles
He must run 4.1 miles to complete the race
The total time is 112 minutes, he used 71 minutes to run the first 9 miles
→ The remaining time = 112 - 71 = 41 minutes
He must finish the 4.1 miles in 41 minutes
→ His average speed for the last part of the race = 4.1 ÷ 41 = 0.1 mi/min
<em>Kevin must run by average speed 0.1 miles/minute to finish the race</em>