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A trained runner's heart beats 50 times a minute at rest, and pushes out 100 mL of blood with each…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A trained runner's heart beats times a minute at rest, and pushes out mL of blood with each beat. While running, it beats times a minute, with mL in each beat. How many litres of blood does the heart pump in a minute at rest, and while running? How many times as much is that?
Need a reminder? The key ideaShow
The heart rate is the number of beats in one minute. Count the pulse at the wrist for a short time, then scale up to s. Blood pumped in a minute = beats in a minute blood in one beat.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. At rest. per minute.
Step 2. Running. per minute.
Step 3. Compare. , about times as much.
Answer: L per minute at rest and L per minute while running, about times as much.
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