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3 years ago

A person has driven a car 180 m in 40 seconds. What is the car’s speed?

Engineering

1 answer:

777dan777 [17]3 years ago

4 0

Answer:

4.5 m/s = 16.2 km/h

Explanation:

The speed is the ratio of distance to time:

speed = (180 m)/(40 s) = 4.5 m/s

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B1) 20 pts. The thickness of each of the two sheets to be resistance spot welded is 3.5 mm. It is desired to form a weld nugget

kap26 [50]

Answer:

minimum current level required = 8975.95 amperes

Explanation:

Given data:

diameter = 5.5 mm

length = 5.0 mm

T = 0.3

unit melting energy = 9.5 j/mm^3

electrical resistance = 140 micro ohms

thickness of each of the two sheets = 3.5mm

Determine the minimum current level required

first we calculate the volume of the weld nugget

v = $\frac{\pi }{4} * D^2 * l$ = $\frac{\pi }{4} * 5.5^2 * 5$ = 118.73 mm^3

next calculate the required melting energy

= volume of weld nugget * unit melting energy

= 118.73 * 9.5 = 1127.94 joules

next find the actual required electric energy

= required melting energy / efficiency

= 1127 .94 / ( 1/3 ) = 3383.84 J

TO DETERMINE THE CURRENT LEVEL REQUIRED use the relation below

electrical energy = I^2 * R * T

3383.84 / R*T = I^2

3383.84 / (( 140 * 10^-6 ) * 0.3 ) = I^2

therefore 8975.95 = I ( current )

4 0

3 years ago

Select four items that an industrial engineer must obtain in order to practice in the field.

alex41 [277]

Answer:

Professional engineering license

Bachelor's degree

Computer science classes

job recommendations

3 0

2 years ago

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The diffusion coefficients for species A in metal B are given at two temperatures:

Kruka [31]

Answer:

a) 149 kJ/mol, b) 6.11*10^-11 m^2/s ,c) 2.76*10^-16 m^2/s

Explanation:

Diffusion is governed by Arrhenius equation

$D = D_0e^{\frac{-Q_d}{RT} }$

I will be using R in the equation instead of k_b as the problem asks for molar activation energy

I will be using

$R = 8.314\ J/mol*K$

and

°C + 273 = K

here, adjust your precision as neccessary

Since we got 2 difusion coefficients at 2 temperatures alredy, we can simply turn these into 2 linear equations to solve for a) and b) simply by taking logarithm

So:

$ln(6.69*10^{-17})=ln(D_0) -\frac{Q_d}{R*(1030+273)}$

and

$ln(6.56*10^{-16}) = ln(D_0) -\frac{Q_d}{R*(1290+273)}$

You might notice that these equations have the form of

$d=y-ax$

You can solve this equation system easily using calculator, and you will eventually get

$D_0 =6.11*10^{-11}\ m^2/s\\ Q_d=1.49 *10^3\ J/mol$

After you got those 2 parameters, the rest is easy, you can just plug them all including the given temperature of 1180°C into the Arrhenius equation

$6.11*10^{-11}e^{\frac{149\ 000}{8.143*(1180+273)}$

And you should get D = 2.76*10^-16 m^/s as an answer for c)

5 0

3 years ago

Advantages of using metal

Contact [7]

Answer:

Metals have high melting points thus unlikely to degrade when temperatures increase, they can be fabricated and are cost effective due to availability.

Explanation:

Aluminum is the most abundant in the Earth's crust with good thermal and electric properties. It is soft, malleable ,ductile and lighter making it a vital metal in construction industry. An alloy of copper and tin, bronze is a better connector of heat and electricity ,commonly used in automobile industry for bearings and springs production. Steel a carbon alloy has applications in forging and automotive.

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3 years ago

What is CQ Thread Ball Valves

hodyreva [135]

That is a thread ball valves

8 0

3 years ago

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