1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
evablogger [386]
3 years ago
12

A person can generate about 300 W of power on a treadmill. If the treadmill is inclined at 3% and a 70-kg man runs at 3 m/s for

45 min, consider the following.(a) Calculate the percentage of the power output that goes into heating up his body. ________%(b) Calculate the percentage that keeps him moving on the treadmill. ___________%(c) How much water would that heat evaporate? Assume the water starts at body temperature, 37 °C. _________kg
Physics
1 answer:
katovenus [111]3 years ago
6 0

Answer:

(a) 79.42 %

(b) 20.58 %

(c) 0.255 kg

Solution:

As per the question:

Power generated by a person, P = 300 W

Inclination of the treadmill from the horizontal, sin\theta = 3% = 0.03

Mass of man, m = 70 kg

Speed, v = 3 m/s

Time taken, t = 45 min = 45\times 60\ s = 2700 s

Now,

Weight of the man, W = mg = 70\times 9.8 = 686\ N

Man's weight component along the inclination of the treadmill, F = mgsin\theta = 686\times 0.03 = 20.58\ N

In order to keep moving the power lost by the man in 1 s is:

P' = Fv = 20.58\times 3 = 61.74\ W

Therefore, the power that is utilized in raising the body temperature of the man:

P'' = P - P' = 300 - 61.74 = 238.26 W

(a) The percentage of the power that is utilized in heating up the body:

%P = \frac{P''}{P}\times 100 = \frac{238.26}{300}\times 100 = 79.42%

(b) Percentage power required to keep the man moving:

%P = \frac{P'}{P}\times 100 = \frac{61.74}{300}\times 100 = 20.58%

(c) Water evaporated by the heat equals the product of the power utilized in raising the body temperature of the man and time:

Heat required to evaporate water, Q = 238.26\times 2700 = 643.302\ kJ

At 37^{\circ}C, heat required for the evaporation of 1 kg of water:

⇒ Heat required to raise the temperature of 1 kg of water at 100^{\circ}C + Heat required for conversion of 1 kg of water into steam at 100^{\circ}C

⇒ mc\Delta T + mL_{v}= 1\times 4186(100 - 37) + 1\times 2256254 = 2519972\ J

where

L_{v} = Latent heat of vaporization

Therefore, mass of water evaporated, m_{w} = \frac{Q}{2519972} = \frac{643302}{2519972} = 0.255\ kg

You might be interested in
A device that uses electricity and magnetism to create motion is called a (motor magnet generator) . In a reverse process, a dev
Tems11 [23]

the answers are a. and c.

I hope I help you out!

6 0
3 years ago
Read 2 more answers
How many bases are there in baseball before reaching home plate?
gregori [183]
There are 3 bases before you reach home plate.
5 0
3 years ago
If the mass of a material is 42 grams and the volume of the material is 15 cm^3, what would the density of the material be?
Fantom [35]

Density = mass / volume

Density = 42g / 15cm^3

Density = 2.8g/cm^3

3 0
3 years ago
Panel A shows a ball shortly after being thrown upward. Panel B shows the same ball in an instant on its way down. Suppose air r
Anna11 [10]

Answer:

ur mom

Explanation:

6 0
3 years ago
Two service technicians are discussing the best way to thread a rod. Technician A says they should use a tap and die set. Techni
Musya8 [376]

Answer:

Both technicians are right, to be able to make a threaded joint you need to use the external thread on one part of the rod using the tap and die set, and on the other side of the rod you need to have an internal thread using the thread repair insert kit

8 0
3 years ago
Other questions:
  • Which metal ion has the “coolest” flame color?<br> What color is it?
    14·2 answers
  • Any kind of wave spreads out after passing through a small enough gap in a barrier. This phenomenon is known as _________. a) di
    11·2 answers
  • Based on Newtons law of universal gravitation, complete the following table.
    15·2 answers
  • If 3,600 J of work is done in 3.0 s, what is the power?
    10·2 answers
  • Your distance and direction from a reference point will define your
    6·1 answer
  • A 1.2 x10 3 kilogram automobile in motion strikes a 1.0 x 10 -4 kilogram insect as a result the insect is accelerated at a rate
    11·1 answer
  • Write an Hypothesis whether land or water heats faster
    11·1 answer
  • How can we use variations in luminosity to set limits on the size of an active galactic nucleus?
    9·1 answer
  • One kg of air contained in a piston-cylinder assembly undergoes a process from an initial state whereT1=300K,v1=0.8m3/kg, to a f
    7·1 answer
  • Which term describes the object that a satellite revolves around?
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!