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3 years ago

Material with hardness of 220 Vickers is harder than material with a hardness of 180 Vickers. a)-True b)- False

Engineering

1 answer:

PSYCHO15rus [73]3 years ago

6 0

Answer:

Correct option a) True.

Explanation:

It is true since the Vickers hardness value refers to the force applied in a 136 ° diamond tip penetrator divided by the surface of the groove produced in the material, the lower the impression made on this greater the value will be end of the Vickers measurement and greater its hardness.

The equation to determine the Vickers hardness value will be:

Hv= ((1.854 × P)/(d²)) (kg/mm²)

Therefore a value of 220 Vickers refers to a harder material than another value of 180 Vickers.

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1. For ball bearings, determine: (a) The factor by which the catalog rating (C10) must be increased, if the life of a bearing un

ElenaW [278]

Answer:

(b) Given the Weibull parameters of example 11-3, the factor by which the catalog rating must be increased if the reliability is to be increased from 0.9 to 0.99.

Equation 11-1: F*L^(1/3) = Constant

Weibull parameters of example 11-3: xo = 0.02 (theta-xo) = 4.439 b = 1.483

Explanation:

(a)The Catalog rating(C)

Bearing life: $L_1 = L , L_2 = 2L$

Catalog rating: $C_1 = C , C_2 = ? ,$

From given equation bearing life equation,

$F\times\frac{1}{3} (L_1) = C_1 ...(1) \\\\ F\times\frac{1}{3} (L_2) =C_2...(2)$

we Dividing eqn (2) with (1)

$\frac{C_2}{C_1} =\frac{1}{3} (\frac{L_2}{L_1})\\\\ C_2 = C*(\frac{2L}{L})\frac{1}{3} \\\\ C_2 = 1.26 C$

The Catalog rating increased by factor of 1.26

(b) Reliability Increase from 0.9 to 0.99

$R_1 = 0.9 , R_2 = 0.99$

Now calculating life adjustment factor for both value of reliability from Weibull parametres

$a_1 = x_o + (\theta - x_o){ ln(\frac{1}{R_1} ) }^{\frac{1}{b}}$

$= 0.02 + 4.439{ ln(\frac{1}{0.9} ) }^{\frac{1}{1.483}} \\\\ = 0.02 + 4.439( 0.1044 )^{0.67}\\\\a_1 = 0.9968$

Similarly

$a_2 = x_o + (\theta - x_o){ ln(\frac{1}{R_2} ) }^{\frac{1}{b} }\\\\ = 0.02 + 4.439{ ln(1/0.99) }^{\frac{1}{1.483} }\\\\ = 0.02 + 4.439( 0.0099 )^{0.67}\\\\a_2 = 0.2215$

Now calculating bearing life for each value

$L_1 = a_1 * LL_1 = 0.9968LL_2 = a_2 * LL_2 = 0.2215L$

Now using given ball bearing life equation and dividing each other similar to previous problem

$\frac{C_2}{C_1} = (\frac{L_2}{L_1} )^{\frac{1}{3} }\\\\ C_2 = C* (\frac{0.2215L }{0.9968L} )^{1/3}\\\\ C_2 = 0.61 C$

Catalog rating increased by factor of 0.61

6 0

4 years ago

1. What is the linear distance traveled in one revolution of a 9 in diameter wheel?

zmey [24]

Explanation:

1. Circumference is pi times diameter.

C = πd

C = 9π inches

C ≈ 28.3 inches

2. Mechanical advantage is ratio of output force to input force.

MA = Fout / Fin

MA = 155 lb / 15 lb

MA ≈ 10.3

3. Mechanical advantage is ratio of input distance over output distance.

MA = din / dout

MA = 10.5 in / 0.85 in

MA ≈ 12.4

4. Mechanical advantage of pulley system is the number of strands.

MA = 8

5. Mechanical advantage is ratio of output force to input force.

MA = Fout / Fin

8 = Fout / 200 lb

Fout = 1600 lb

5 0

4 years ago

. Ropes made from are typically very weak.

Umnica [9.8K]

Answer: cotton and/or known as Cotton rope

Explanation: It is a very weak fiber that has less strength than cotton. So its typically very weak

6 0

3 years ago

ladders are not required to be inspected for visible defects prior to the first use of each work shift,and after any occuurrence

zaharov [31]

Answer:

The answer is False.

Explanation:

When it comes to occupational safety, it is very important for ladders to be inspected by a qualified person before each use. This is because ladders undergo conditions that impact their integrity while being in use. The inspection is also essential in order for the ladder to be timely replaced.

Ladder accidents or ladder-related injuries happen every year. Around 700 occupational deaths due to elevated fall from a ladder accounts for 15% of all occupational deaths. Misuse or damage ladders are often the reasons for this.

Thus, the answer in the above statement is False because ladders are required to be inspected for visible defects prior to the first use of each work shift and after any occurrence that could affect their safety.

4 0

3 years ago

Decide whether or not the Final Value Theorem is applicable to the following functions. If not, indicate why you cannot apply it

LUCKY_DIMON [66]

Answer:

a) Yes applicable, x(∞) = 0

b) Yes applicable, x(∞) = 0

Explanation:

Final Value Theroem indicates that final value of x(t) can be found by Laplace Transform X(s) as follows:

$x(\infty)= \lim\limits_{s \to0} sX(s)$