In an investigation, a person ran at different speeds - Edexcel - GCSE Biology - Question 3 - 2013 - Paper 1
Question 3
In an investigation, a person ran at different speeds.
(a) The graph shows the concentration of lactic acid in the blood and the heart rate of this person while run... show full transcript
Worked Solution & Example Answer:In an investigation, a person ran at different speeds - Edexcel - GCSE Biology - Question 3 - 2013 - Paper 1
Step 1
Calculate the heart rate at 22 km h⁻¹
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
From the graph, the heart rate corresponding to a running speed of 22 km h⁻¹ is around 198 to 200 beats per minute. For calculation, we can use an average heart rate of 199 beats per minute.
Step 2
Use the cardiac output formula
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the formula:
cardiac output=stroke volume×heart rate
Substituting the values:
cardiac output=0.18 dm3×199 beats/min
Step 3
Calculate the cardiac output
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Calculating the above expression gives:
cardiac output=35.82 dm3/min
Rounding off, the cardiac output is approximately 36 dm³ per minute.