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
olga nikolaevna [1]
3 years ago
11

A boy weighing 108-lb starts from rest at the bottom A of a 6-percent incline and increases his speed at a constant rate to 7 mi

/hr as he passes B, 40 ft along the incline from A. Determine his power output as he approaches B.
Engineering
1 answer:
baherus [9]3 years ago
4 0

Answer:

88.18 W

Explanation:

The weight of the boy is given as 108 lb

Change to kg =108*0.453592= 48.988 kg = 49 kg

The slope is given as 6% , change it to degrees as

6/100 =0.06

tan⁻(0.06)= 3.43°

The boy is travelling at a constant speed up the slope = 7mi/hr

Change 7 mi/h to m/s

7*0.44704 =3.13 m/s

Formula for power P=F*v where

P=power output

F=force

v=velocity

Finding force

F=m*g*sin 3.43°

F=49*9.81*sin 3.43° =28.17

Finding the power out

P=28.17*3.13 =88.18 W

You might be interested in
Refrigerant-134a at 400 psia has a specific volume of 0.1144 ft3/lbm. Determine the temperature of the refrigerant based on (a)
vekshin1

Answer:

a) Using Ideal gas Equation, T = 434.98°R = 435°R

b) Using Van Der Waal's Equation, T = 637.32°R = 637°R

c) T obtained from the refrigerant tables at P = 400 psia and v = 0.1144 ft³/lbm is T = 559.67°R = 560°R

Explanation:

a) Ideal gas Equation

PV = mRT

T = PV/mR

P = pressure = 400 psia

V/m = specific volume = 0.1144 ft³/lbm

R = gas constant = 0.1052 psia.ft³/lbm.°R

T = 400 × 0.1144/0.1052 = 434.98 °R

b) Van Der Waal's Equation

T = (1/R) (P + (a/v²)) (v - b)

a = Van Der Waal's constant = (27R²(T꜀ᵣ)²)/(64P꜀ᵣ)

R = 0.1052 psia.ft³/lbm.°R

T꜀ᵣ = critical temperature for refrigerant-134a (from the refrigerant tables) = 673.6°R

P꜀ᵣ = critical pressure for refrigerant-134a (from the refrigerant tables) = 588.7 psia

a = (27 × 0.1052² × 673.6²)/(64 × 588.7)

a = 3.596 ft⁶.psia/lbm²

b = (RT꜀ᵣ)/8P꜀ᵣ

b = (0.1052 × 673.6)/(8 × 588.7) = 0.01504 ft³/lbm

T = (1/0.1052) (400 + (3.596/0.1144²) (0.1144 - 0.01504) = 637.32°R

c) The temperature for the refrigerant-134a as obtained from the refrigerant tables at P = 400 psia and v = 0.1144 ft³/lbm is

T = 100°F = 559.67°R

7 0
3 years ago
A sand has a natural water content of 5% and bulk unit weight of 18.0 kN/m3. The void ratios corresponding to the densest and lo
Zinaida [17]

Answer:

Relative density = 0.545

Degree of saturation = 24.77%

Explanation:

Data provided in the question:

Water content, w = 5%

Bulk unit weight = 18.0 kN/m³

Void ratio in the densest state, e_{min} = 0.51

Void ratio in the loosest state, e_{max} = 0.87

Now,

Dry density, \gamma_d=\frac{\gamma_t}{1+w}

=\frac{18}{1+0.05}

= 17.14 kN/m³

Also,

\gamma_d=\frac{G\gamma_w}{1+e}

here, G = Specific gravity = 2.7 for sand

17.14=\frac{2.7\times9.81}{1+e}

or

e = 0.545

Relative density = \frac{e_{max}-e}{e_{max}-e_{min}}

= \frac{0.87-0.545}{0.87-0.51}

= 0.902

Also,

Se = wG

here,

S is the degree of saturation

therefore,

S(0.545) = (0.05)()2.7

or

S = 0.2477

or

S = 0.2477 × 100% = 24.77%

7 0
3 years ago
A sample of municipal sewage is diluted to 1% by volume prior to running a BOD5 analysis. After 5 days the oxygen consumption is
liberstina [14]

Answer:

BOD5 = 200 mg/L

Explanation:

given data

diluted = 1% = 0.01

time = 5 day

oxygen consumption = 2.00 mg · L−1

solution

we get here BOD5  that is BOD after 5 day

and here total volume is 100% = 1

so dilution factor is \frac{100}{1}    =  100

so BOD5 is

BOD5 = oxygen consumption × dilution factor

BOD5 = 2 × 100

BOD5 = 200 mg/L

4 0
3 years ago
A long, horizontal, pressurized hot water pipe of 15cm diameter passes through a room where the air temperature is 24degree C. T
solmaris [256]

Answer:

Rate of heat transfer to the room air per meter of pipe length equals 521.99 W/m

Explanation:

Since it is given that the radiation losses from the pipe are negligible thus the only mode of heat transfer will be by convection.

We know that heat transfer by convection is given by

\dot{Q}=hA(T-T_{\infty })

where,

h = heat transfer coefficient = 10.45 W/m^{2}K (free convection in air)

A = Surface Area of the pipe

Applying the given values in the above formula we get

\dot{Q}=10.45\times \pi DL\times (130+273-(24+273))\\\\\frac{\dot{Q}}{L}=10.45\times 0.15\times \pi \times (130-24)\\\\\frac{\dot{Q}}{L}=521.99W/m

5 0
3 years ago
Why we use the lagrange Equation? ​
PIT_PIT [208]

Answer:

It is used for solving optimization problems in which,given some functional,one seeks the function minimizing or minimizing it.

Explanation:

Please i need a Brainliest.

3 0
3 years ago
Other questions:
  • The period of a pendulum T is assumed to depend only on the mass m, the length of the pendulum `, the acceleration due to gravit
    9·1 answer
  • You are an engineer working in a auto crash test lab. Some members of your team have raised objections against the use of cadave
    10·1 answer
  • Air at 400 kPa, 980 K enters a turbine operating at steady state and exits at 100 kPa, 670 K. Heat transfer from the turbine occ
    9·1 answer
  • How many volts of electricity would it take to power up an entire city? Take Tokyo for example. Please explain!
    12·1 answer
  • What are two reasons why Hunter edjucation is important?<br><br><br> 30 pts
    12·1 answer
  • Dalton needs to prepare a close-out report for his project. Which part of the close-out report would describe
    6·1 answer
  • Can someone explain the answer for this question please? -metrology
    12·1 answer
  • What parts do all circuits have in common?
    9·2 answers
  • Is there a project idea, or invention that would be good for<br> my class.
    6·2 answers
  • Write a system of equations to describe the situation below, solve using any method, and fill in the blanks.
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!