Answer:
Explanation:if you stretch the hose more tightly the speed of the pulse will reduce..
Answer:
square cross section. The bar is made of a 7075-T6 aluminum alloy which has a yield strength of 500 MPa, a tensile strength of 575 MPa, and a fracture toughness of 27.5 MPaâm.
Required:
a. What is the nominal maximum tensile stress on the bar?
b. If there were an initial 1.2 mm deep surface crack on the right surface of the bar, what would the critical stress needed to cause instantaneous fast fracture of the bar be?
Answer:
a)
, b) 
Explanation:
a) The counterflow heat exchanger is presented in the attachment. Given that cold water is an uncompressible fluid, specific heat does not vary significantly with changes on temperature. Let assume that cold water has the following specific heat:

The effectiveness of the counterflow heat exchanger as a function of the capacity ratio and NTU is:

The capacity ratio is:



Heat exchangers with NTU greater than 3 have enormous heat transfer surfaces and are not justified economically. Let consider that
. The efectiveness of the heat exchanger is:


The real heat transfer rate is:




The exit temperature of the hot fluid is:




The log mean temperature difference is determined herein:



The heat transfer surface area is:



Length of a single pass counter flow heat exchanger is:



b) Given that tube wall is very thin, inner and outer heat transfer areas are similar and, consequently, the cold side heat transfer coefficient is approximately equal to the hot side heat transfer coefficient.

Answer:
The strength coefficient is K = 591.87 MPa
Explanation:
We can calculate the strength coefficient using the equation that relates the tensile strength with the strain hardening index given by

where Sut is the tensile strength, K is the strength coefficient we need to find and n is the strain hardening index.
Solving for strength coefficient
From the strain hardening equation we can solve for K

And we can replace values

Thus we get that the strength coefficient is K = 591.87 MPa
Answer:
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