All categories

3 years ago

PLEASE HELP

Engineering

2 answers:

lyudmila [28]3 years ago

6 0

Answer:

Air

Explanation:

QveST [7]3 years ago

5 0

I think air I may be wrong

You might be interested in

Practice Problem: True Stress and Strain A cylindrical specimen of a metal alloy 49.9 mm long and 9.72 mm in diameter is stresse

Valentin [98]

Answer:

The true stress required = 407 MPa

Explanation:

True Stress is the ratio of the internal resistive force to the instantaneous cross-sectional area of the specimen. True Strain is the natural log to the extended length after which load applied to the original length. The cold working stress – strain curve relation is as follows,

σ(t) = K (ε(t))ⁿ, σ(t) is the true stress, ε(t) is the true strain, K is the strength coefficient and n is the strain hardening exponent

True strain is given by

Epsilon t =㏑ (l/l₀)

Substitute㏑(l/l₀) for ε(t)

σ(t) = K(㏑(l/l₀))ⁿ

Given values l₀ = 49.9mm, l =53.5mm , n =0.1 , σ(t) =376Mpa

376 x 10⁶ = K (㏑(53.5/49.9))^0.1

K = 376 x 10⁶/(㏑(53.5/49.9))^0.1

K = 490.78 MPa

Knowing the constant value would be same as the same material is being used in the second test, we can find out the true stress using the above formula replacing the value of the constant.

σ(t) = K(㏑(l/l₀))ⁿ

l₀ = 49.9mm, l = 58.2mm, n = 0.1, K = 490.78Mpa

σ(t) = 490.78 x 10⁶ x (㏑(58.2/49.9))^0.1

σ(t) = 407 MPa

The true stress necessary to plastically elongate the specimen is 407 MPa.

5 0

3 years ago

A circuit contains four 100 ohm resistors connected in series. If you test the circuit with a DMM you should read a total resist

olga nikolaevna [1]

C is the correct answer

8 0

3 years ago

Water at 20oC, with a free-stream velocity of 1.5 m/s, flows over a circular pipe with diameter of 2.0 cm and surface temperatur

Lisa [10]

Answer:

Average heat transfer coefficient = 31 kw/m^2 k

Heat transfer rate per meter length of pipe = 116.808 KW

Explanation:

water temperature = 20⁰c,

free-stream velocity = 1.5 m/s

circular pipe diameter = 2.0 cm = 0.02 m

surface temperature = 80⁰c

A) calculate average heat transfer coefficient

we apply the formula below :

m = αAv

A (area) = $\pi /4 (d)^2$

m = 10^3 * $\pi / 4 ( 0.02)^2$ * 1.5

= 10^3 * 0.7857( 0.0004) * 1.5

= 0.4714 kg/s

Average heat transfer coefficient

h = $\frac{m(cp)}{A}$ , A = $\pi DL$

L = 1 m , m = 0.4714 kgs , cp = 4.18

back to equation

h = $\frac{0.4714*4.18}{\pi * 0.02 }$ = 1.970 / 0.0628 = 31.369 ≈ 31 kw/m^2 k

B) Heat transfer rate per meter length of pipe

Q = ha( ΔT ), a = $\pi DL$

= 31 * 0.0628 * ( 80 - 20 )

= 31 * 0.0628 * 60 = 116.808 KW

3 0

3 years ago

What is the scope of hazard review in a worksite analysis

Brums [2.3K]

Answer:

A job hazard analysis is a technique that focuses on job tasks as a way to identify hazards before they occur. It focuses on the relationship between the worker, the task, the tools, and the work environment. After uncontrolled hazards are identified, take action to eliminate them or reduce risk.

5 0

3 years ago

The statement that is NOT true about the difference between laminar and turbulent boundary layers is:1.the Reynolds number for a

IgorLugansk [536]

Answer:

4. The velocity gradient at the wall is greater for a laminar boundary layer than a turbulent boundary layer.

Explanation:

This is false

6 0

4 years ago