Chapter 2: Flashcards
(12 cards)
Describe the changes in gravitational potential energy as blood goes from the heart, to the peripheral tissue, and back to the heart:
- Heart to lungs - Blood raises up slightly, causing an increase in gravitational potential energy.
- As blood goes back to the heart it will go back to the initial gravitational potential energy.
- As blood leaves the heart and goes up the aorta, the gravitational potential energy will slightly increase.
- As blood leaves the aorta and goes into peripheral vessels, the gravitational potential energy will drastically decrease.
- As blood returns to the heart via venous return, gravitational potential energy is slowly (venous return is slow) increasing back to the initial gravitational potential energy.
DRAW OUT AS A GRAPH!
What is the relationship between power (Joules/second) and potential (volts)?
Power is directly proportional to volts, through the following equation:
P = I* V
Joules are a measure of:
energy.
Power is a measure of:
energy/time (J/s)
Electric shock plates are sometimes used to restore the natural rhythm after a heart attack. The shock plates run off a 10-V battery and draw a current of 23 amps. If each shock draws 250 joules of energy, what is the duration of the shock?
1) P = VI
P = (10 v) * (23 amps) = 230 J/s
2) Power = Energy/time
Time = Energy/power
(250 J)/(230 J/s) = 1.09 seconds.
If a conductive cell in the heart produces an electrical current of 2 amps, which ultimately produces a real power of 35 to be used for muscle contraction of the heart. What would be the electrical potential of this cell?
P = VI
V = P/I
V = (35 j/s)/(2 amps) = 17.5 volts.
Define work:
The amount of energy transferred from one object to another due to a displacing force. This is measured in joules. A question that says “energy used” “energy transferred”, etc, is referring to work.
What are 3 relevant equations for work?
1) W = F (force) * d (displacement)
2) P = W/t
3) W = mgheight
A researcher is experimenting on the impacts of the force of increasingly high winds against wind turbine function and longevity. The researcher uses a pulley system to move her 68-Kg gear to the top of a 108-meter-tall turbine. How much work is being done?
a. 80,000 joules.
b. 72 joules.
c. 72,000 joules.
d. 800 joules.
1) this question is asking bout the amount of work to move an object, not about the kinematics of wind.
2) W = mgh = f*d
W = (68 Kg)(9.8 m/s^2)(108 m) = 72,000 joules.
Define potential energy:
Stored energy that is available to be used. When a ball is at the top of a hill it holds a large amount of potential energy, which will be released as the ball rolls down.
As a person swallows a bolus of chewed food, the food will move down their esophagus and toward the stomach. Which of the following would be most accurate?
a. The kinetic energy of the bolus will increase.
b. The acceleration of the bolus will remain constant, but the mass will increase.
c. The bolus will increase in temperature.
d. The gravitational potential energy of the bolus will decrease.
d. The gravitational potential energy of the bolus will decrease.
What is the relationship between gravitational potential energy and position?
As your position gets closer to the ground (decrease in height), gravitational potential energy will decrease. Height and gravitational potential energy are directly proportional.
