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zimovet [89]
3 years ago
6

Unlike expendable molds, permanent molds do not collapse, so the mold must be opened before appreciable cooling contraction occu

rs in order to prevent cracks from developing in the casting: True or False
Engineering
1 answer:
Pani-rosa [81]3 years ago
8 0

Answer: True

Explanation:

Permanent molds do not collapse, unlike expendable molds so the mold must be opened before appreciable cooling contraction occurs in order to prevent cracks from developing in the casting.

The metal casting becomes solid inside the mold after it has been poured. But during the process of manufacture, before the would cools any further, they usually remove the metal cast in order to stop excess contractions of the solid metal casting in the mold. This is done to prevent prevent cracks from developing in the casting since permanent mold do not collapse.

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How many parts (screws and bolts included) does the average car have?
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A single car has about 30,000 parts, counting every part down to the smallest screws
5 0
3 years ago
Read 2 more answers
5. The water in an 8-m-diameter, 3-m-high above-ground swimming pool is to be emptied by unplugging a 3-cm-diameter, 25-m-long h
frosja888 [35]

Answer:

The maximum discharge rate of water through the pipe is 0.00545 m³/s or 5.45 L/s.

Friction head and pressure head will cause the actual flow rate to be less.

Explanation:

Considering point 1 at the free surface of the pool, and point 2 at the exit of

pipe.

Using Bernoulli equation between

these two points simplifies to

P1/(p*g) + V1²/2g + z1 = P2/(p*g) + V2²/2g + z2

Let the reference level at the pipe exit (z2 = 0). Noting that the fluid at both points is open to the atmosphere (and thus P1 = P2 = Patm) and that the fluid velocity at the free surface is very low (V1 ≅ 0),

P/(p*g) + z1 = P/(p*g) + V2²/2g

z1 = V2²/2g

Note; z1 = h

V2max = √2gh

h = 3 m

V2max = √2 * 9.81 * 3

V2max = √58.86 = 7.67 m/s

maximum discharge rate of water through the pipe Qmax = Area A * Velocity of discharge V2max

Qmax = A * V2max

Diameter d = 3 cm = 0.03 m

A = Πd²/4 = (Π * 0.03²)/4 = 0.00071m³

Qmax = 0.00071 * 7.67 = 0.00545 m³/s

Qmax = 5.45 L/s

The maximum discharge rate of water through the pipe is 0.00545 m³/s or 5.45 L/s.

Actual flow rate will be less because of heads such as friction head and pressure head.

7 0
3 years ago
A blown fuse or tripped circuit breaker shows
aleksklad [387]

Answer:

Your house is in need of a service upgrade, or it may indicate that your house has too few circuits.

Explanation:

It's a sign that you are making excessive demands on the circuit and need to move some appliances and devices to other circuits.

6 0
3 years ago
Which of the following is correct regarding the principal stresses and maximum in-plane shear stresses? a. Principal stresses ca
ziro4ka [17]

Answer:

option B.

Explanation:

The correct answer is option B.

Principal stress is the maximum normal stress a body can have. In principal stress, there is purely normal stress. On principal plane shear stress is zero.

In-plane shear stress are the shear stress which is acting on the plane.

The statement which is correct regarding principle plane and shear stress is that The shear stress over principal stress planes is always zero.

4 0
3 years ago
For beam design, the cross section dimensions of the beam are determined: A. Based on allowable normal stress, but the allowable
noname [10]

Answer:

B. Based on the allowable shear stress, but the allowable normal stress should always be checked to be sure it is not exceeded

Explanation:

Shear stress is analyzed to determine the shear forces along the lenght of the beam. This is represented in a shear force diagram. The beam cross sectional design is determined in such a way as to minimize the shear stress. Allowable normal stress should always be checked in a structure if failure is to be prevented.

8 0
3 years ago
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