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
belka [17]
3 years ago
5

5) A 80-kg man has a total foot imprint area of 480 cm2. Determine the pressure this man exerts on the ground if (a) he stands o

n both feet and (b) he stands on one foot.
Engineering
1 answer:
attashe74 [19]3 years ago
4 0

Answer:

The pressure exerted by this man on ground

(a) if he stands on both feet is 8.17 KPa

(b) if he stands on one foot is 16.33 KPa

Explanation:

(a)

When the man stand on both feet, the weight of his body is uniformly distributed around the foot imprint of both feet. Thus, total area in this case will be:

Area = A = 2 x 480 cm²

A = 960 cm²

A = 0.096 m²

The force exerted by man on his area will be equal to his weight.

Force = F = Weight

F = mg

F = (80 kg)(9.8 m/s²)

F = 784 N

Now, the pressure exerted by man on ground will be:

Pressure = P = F/A

P = 784 N/0.096 m²

<u>P = 8166.67 Pa = 8.17 KPa</u>

(b)

When the man stand on one foot, the weight of his body is uniformly distributed around the foot imprint of that foot only. Thus, total area in this case will be:

Area = A = 480 cm²

A = 0.048 m²

The force exerted by man on his area will be equal to his weight, in this case, as well.

Force = F = Weight

F = mg

F = (80 kg)(9.8 m/s²)

F = 784 N

Now, the pressure exerted by man on ground will be:

Pressure = P = F/A

P = 784 N/0.048 m²

<u>P = 16333.33 Pa = 16.33 KPa</u>

You might be interested in
A composite wall is to be used to insulate a freezer chamber at -350C. Two insulating materials are to be used with conductiviti
choli [55]

Answer:

thickness1=1.4m

thickness2=2.2m

convection coefficient=0.33W/m^2K

Explanation:

you must use this equation to calculate the thickness:

L=K(T2-T1)/Q

L=thickness

T=temperature

Q=heat

L1=0.04*(0--350)/10=1.4m

L2=0.1(220-0)/10=2.2m

Then use this equation to calculate the convective coefficient

H=Q/(T2-T1)

H=10/(250-220)=0.33W/m^2K

7 0
3 years ago
__________ affect(s) the amount of air conditioning required.
Grace [21]

Answer:

Option D

All the above

Explanation:

Depending with the number of occupants in a building, the number of air conditioners required can either be increased or reduced. For instance, if the building is to be a classroom of over 50 students, 1 air-conditioner can't serve effectively. Similarly, the activity of occupants also dictate the amount of air conditioners required since if it's a gym room where occupants exercise often then the air conditioners required is different from if the room was to serve as a  lounge. The appliances that also operate in a room require that air conditioners be installed as per the heat that may be generated by the appliances.

5 0
3 years ago
What is the best engineering job to do? Why?
allochka39001 [22]

Answer:

Any engineering job would be good YOU should be the one choosing which job.

Explanation:

Engineering is a great outlet for the imagination, and the perfect field for independent thinkers.

7 0
2 years ago
Read 2 more answers
In the engineering design process, testing is the least important step.<br> True<br> False
Wittaler [7]

Answer:

false

Explanation:

7 0
3 years ago
Read 2 more answers
Methane gas is 304 C with 4.5 tons of mass flow per hour to an uninsulated horizontal pipe with a diameter of 25 cm. It enters a
Arada [10]

Answer:

a) h_c = 0.1599 W/m^2-K

b) H_{loss} = 5.02 W

c) T_s = 302 K

d) \dot{Q} = 25.125 W

Explanation:

Non horizontal pipe diameter, d = 25 cm = 0.25 m

Radius, r = 0.25/2 = 0.125 m

Entry temperature, T₁ = 304 + 273 = 577 K

Exit temperature, T₂ = 284 + 273 = 557 K

Ambient temperature, T_a = 25^0 C = 298 K

Pipe length, L = 10 m

Area, A = 2πrL

A = 2π * 0.125 * 10

A = 7.855 m²

Mass flow rate,

\dot{ m} = 4.5 tons/hr\\\dot{m} = \frac{4.5*1000}{3600}  = 1.25 kg/sec

Rate of heat transfer,

\dot{Q} = \dot{m} c_p ( T_1 - T_2)\\\dot{Q} = 1.25 * 1.005 * (577 - 557)\\\dot{Q} = 25.125 W

a) To calculate the convection coefficient relationship for heat transfer by convection:

\dot{Q} = h_c A (T_1 - T_2)\\25.125 = h_c * 7.855 * (577 - 557)\\h_c = 0.1599 W/m^2 - K

Note that we cannot calculate the heat loss by the pipe to the environment without first calculating the surface temperature of the pipe.

c) The surface temperature of the pipe:

Smear coefficient of the pipe, k_c = 0.8

\dot{Q} = k_c A (T_s - T_a)\\25.125 = 0.8 * 7.855 * (T_s - 298)\\T_s = 302 K

b) Heat loss from the pipe to the environment:

H_{loss} = h_c A(T_s - T_a)\\H_{loss} = 0.1599 * 7.855( 302 - 298)\\H_{loss} = 5.02 W

d) The required fan control power is 25.125 W as calculated earlier above

5 0
3 years ago
Other questions:
  • The hot and cold inlet temperatures to a concentric tube heat exchanger are Th,i = 200°C, Tc,i = 100°C, respectively. The outlet
    10·1 answer
  • Which of the following is not a primary or fundamental dimension? (a)-mass m (b)-length L (c)- timer t (d)-volume V
    5·1 answer
  • A venturi meter is to be installed in a 63 mm bore section of a piping system to measure the flow rate of water in it. From spac
    15·1 answer
  • A hot-water stream at 80°C enters a mixing chamber with a mass flow rate of 0.46 kg/s where it is mixed with a stream of cold wa
    14·1 answer
  • a stem and leaf display describes two-digit integers between 20 and 80. for one one of the classes displayed, the row appears as
    6·1 answer
  • Which is the required type of fire extinguisher for standard naval vessels
    9·1 answer
  • Refrigerant-134a enters an adiabatic compressor at -30oC as a saturated vapor at a rate of 0.45 m3 /min and leaves at 900 kPa an
    13·1 answer
  • List a minimum of four reasons why you might be rejected for a job offer.
    10·1 answer
  • An ideal Rankine cycle with reheat uses water as the working fluid. The conditions at the inlet to the first-stage turbine are p
    12·1 answer
  • which acpi power state allows a system to start where it left off, but all other components are turned off? sleeping mechanical
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!