The amount of work done by the heart’s main pumping chamber, the left ventricle, is given by the equation

where W is the work per unit time, P is the average blood pressure, V is the volume of blood pumped out during the unit of time, δ (“delta”) is the weight density of the blood, v is the average velocity of the exiting blood, and g is the acceleration of gravity. When P, V, d, and v remain constant, W becomes a function of g, and the equation takes the simplified form

As a member of NASA’s medical team, you want to know how sensitive W is to apparent changes in g caused by flight maneuvers, and this depends on the initial value of g. As part of your investigation, you decide to compare the effect on W of a given change dg on the moon, where g = 5.2 ft/sec², with the effect the same change dg would have on Earth, where g = 32 ft/sec². Use the simplified equation above to find the ratio of dW_moon to dW_Earth.

Transcribed Image Text:

W = PV + V8v² 2g