Question

At a resting pulse rate of 77 beats per minute, the human heart typically pumps about 65 mL of blood per beat. Blood has a denstity of 1060 kg / m3. Circulating all of the blood in the body through the heart takes about 1 min for a person at rest. (a) How much blood is in the body? (b) On average, what mass of blood does the heart pump with each heart beat?

Answer 1

Given:
1 minute circulation
77 beats per minute
65 ml of blood per beat
blood density of 1060kg/m³

a) how much blood is in the body?

77 beats per min * 65ml per beat = 5,005 ml per minute

5,005ml * 1l/1000ml = 5.0005 Liters.

I'm not sure on how to solve for question b.

Answer 2

(a) Blood in the body is 77*65 = 5005 ml

(b) On average, mass of blood does the heart pump with each heart beat is 68.9 g

Explanation:

Given : At a resting pulse rate of 77 beats per minute, the human heart typically pumps about 65 mL of blood per beat. Blood has a denstity of 1060 kg / m3. Circulating all of the blood in the body through the heart takes about 1 min for a person at rest

To Find: (a) How much blood is in the body?

(b) On average, what mass of blood does the heart pump with each heart beat?

Solution :

Since we are given that heart beats per minute =77

And Heart pumps about 65 mL of blood per beat

(a) So, blood in the body is 77*65 = 5005 ml

Since mass = volume * density

⇒ so, mass of blood does the heart pump with each heart beat = volume * density

⇒mass =
`65 ml *1060kg/m^(3)`

`1ml = 10^(-6) m^(3)`

Thus 65 ml =
`65*10^(-6) m^(3)`

⇒mass =
`65*10^(-6) m^(3) *1060kg/m^(3)`

⇒mass =
`68900*10^(-6)`

⇒mass =
`689*10^(-4)`

⇒mass =
`689*10^(-3)*10^(-1)`

⇒mass =
`68.9*10^(-3) kg`

⇒mass =
`68.9grams`

(b) On average, mass of blood does the heart pump with each heart beat is 68.9 g