Tutorial Questions
Fluids
Question 1
The human lungs can function satisfactorily up to a limit where the pressure difference
between the outside and inside of the lungs is one-twentieth of an atmosphere. If a diver uses
a snorkel for breathing, how far below the water can she swim? Assume the diver is in salt
water whose density is 1025 kg/m3.
Question 2
A patient recovering from surgery is being given fluid intravenously. The fluid has a density
of 1030 kg/m3, and 9.5 x 10-4 m3 of it flows into the patient every six hours. Find the mass
flow rate in kg/s.
Temperature and Heat
Question 3
On a sunny day, the temperature of a patient was recorded by an intern as 312.35 K, what is
the equivalent temperature in Celcius and Fahrenheit.
Question 4
When you drink cold water, your body must expend metabolic energy in order to maintain
normal body temperature (37 °C) by warming up the water in your stomach. Could drinking
ice water, then, substitute for exercise as a way to “burn calories?” Suppose you expend 430
kilocalories during a brisk hour-long walk. How many liters of ice water (0 °C) would you
have to drink in order to use up 430 kilocalories of metabolic energy? For comparison, the
stomach can hold about 1 liter.
Question 5
A person eats a container of strawberry yogurt. The Nutritional Facts label states that it
contains 240 Calories (1 Calorie = 4186 J). What mass of perspiration would one have to lose
to get rid of this energy? At body temperature, the latent heat of vaporization of water is 2.42
x 106 J/kg
The Transfer of Heat
Question 6
The amount of heat per second conducted from the blood capillaries beneath the skin to the
surface is 240 J/s. The energy is transferred a distance of 2.0 x 1023 m through a body whose
surface area is 1.6 m2. Assuming that the thermal conductivity is that of body fat, determine
the temperature difference between the capillaries and the surface of the skin. (the thermal
conductivity of body fat is 0.2 J/(s.m.oC)
Fluids
Question 1
The human lungs can function satisfactorily up to a limit where the pressure difference
between the outside and inside of the lungs is one-twentieth of an atmosphere. If a diver uses
a snorkel for breathing, how far below the water can she swim? Assume the diver is in salt
water whose density is 1025 kg/m3.
Question 2
A patient recovering from surgery is being given fluid intravenously. The fluid has a density
of 1030 kg/m3, and 9.5 x 10-4 m3 of it flows into the patient every six hours. Find the mass
flow rate in kg/s.
Temperature and Heat
Question 3
On a sunny day, the temperature of a patient was recorded by an intern as 312.35 K, what is
the equivalent temperature in Celcius and Fahrenheit.
Question 4
When you drink cold water, your body must expend metabolic energy in order to maintain
normal body temperature (37 °C) by warming up the water in your stomach. Could drinking
ice water, then, substitute for exercise as a way to “burn calories?” Suppose you expend 430
kilocalories during a brisk hour-long walk. How many liters of ice water (0 °C) would you
have to drink in order to use up 430 kilocalories of metabolic energy? For comparison, the
stomach can hold about 1 liter.
Question 5
A person eats a container of strawberry yogurt. The Nutritional Facts label states that it
contains 240 Calories (1 Calorie = 4186 J). What mass of perspiration would one have to lose
to get rid of this energy? At body temperature, the latent heat of vaporization of water is 2.42
x 106 J/kg
The Transfer of Heat
Question 6
The amount of heat per second conducted from the blood capillaries beneath the skin to the
surface is 240 J/s. The energy is transferred a distance of 2.0 x 1023 m through a body whose
surface area is 1.6 m2. Assuming that the thermal conductivity is that of body fat, determine
the temperature difference between the capillaries and the surface of the skin. (the thermal
conductivity of body fat is 0.2 J/(s.m.oC)
