- #1
ryant14
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Homework Statement
The lower chamber of the heart, (the left ventricle) pumps blood into aorta. The left ventricular contraction lasts 0.20 seconds, during which time a mass of 88 grams of blood is accelerated from rest to a speed of about 4.5 m/s. Find the acceleration & Force.
known:
V final - 4.5 m/s
V initial - 0 m/s
Mass - 88 grams or 0.088 kg
Time it takes for contraction - 0.20 s
Homework Equations
a = (vf - vi)/t
Summation of horiontal force (F) = ma
The Attempt at a Solution
a = (4.5 m/s - 0 m/s) / 0.20
= 22.5 m/s^2
F= ma
= (0.088kg)(22.5 m/s^2)
These were my answers but my professor marked it wrong. according to him the acceleration should not exceed than 4.5 m/s^2 and the Force must not be greater than 1 Newton.
are my interpretations to this problem wrong?
Is it correct that I've used 0.20 seconds as a time to get the acceleration?
I am confused about this, "The left ventricular contraction lasts 0.20 seconds, during which time a mass of 88 grams of blood is accelerated from rest to a speed of about 4.5 m/s."
What does this mean? Is it right that the 88 g of blood obtains 4.5 m/s of final speed at 0.20 seconds or not? Or after 0.20 seconds, the blood starts moving?
Please help...
Thanks in advance :)