(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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

2. Relevant equations

a = (vf - vi)/t

Summation of horiontal force (F) = ma

3. 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 :)

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# Homework Help: Newton's law of Motion problem

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