Answer:
t=5.5 mm
Heat dissipation per unit length = 90.477 W/m
Explanation:
Given that
Diameter d = 5 mm ⇒r = 2.5 mm
Conductivity of insulated material K = 0.16 W/mK
Heat transfer coefficient = 20
When thickness reaches up to critical radius of insulation then heat dissipation will be maximum
We know that critical radius of insulation of wire is given as follow
Now by putting the values
So the thickness of insulation
t=8-2.5 mm
t=5.5 mm
As we know that heat transfer due to convection given as follows
Q = hAΔ T
Q=20 x 2 x π x 0.008 x (120-30)
Q = 90.477 W/m
So heat dissipation per unit length = 90.477 W/m
Answer:
Fatigue lifetimes will be ranked as B>A>C
Explanation:
Start by calculating the mean stress for all samples
σa= (σamax + σamin)/2 = (450 - 350)/2 = 50MPa
σb= (σbmax + σbmin)/2 = (400 - 300)/2 = 50MPa
σa= (σcmax + σcmin)/2 = (340 - 340)/2 = 0MPa
Now calculate the stress amplitudes of all three samples
σa= (σamax - σamin)/2 = (450 + 350)/2 = 400MPa
σb= (σbmax - σbmin)/2 = (400 + 300)/2 = 350MPa
σc= (σcmax - σcmin)/2 = (340 + 340)/2 = 340MPa
The mean stress of samples A and B is the same which is higher than sample C. Hence samples A and B will have a higher fatigue life than sample C. However, the higher stress amplitude means lower fatigue life, hence, sample B will have a higher fatigue life than sample A. So the order will be B> A> C.
Attached picture shows the justification using and S- N plot.
Answer:
Because older cars didn't really have much power steering, and parking or even turning at low speeds could require a lot of strength to move the steering wheel on a big, heavy car. This moves the rack to the right or left, which turns the vehicle's wheels. Without power assist, you'd need grunt force to turn the pinion and move the rack.
Explanation:
Answer:
The material that is not used for wood sanding is
3. Emery
Explanation:
The materials recommended for use as materials for wood sanding includes;
1) Garnet paper is a very brittle moderately hard, self sharpening and durable material which is a popular choice of most woodworkers
2) Aluminum oxide is used for the sanding of hardwood
3) Emery is used for the smoothening of a metal surface
4) Silicon carbide has a faster effect rate than aluminum oxide, and it is used to smoothen woodwork objects
Therefore, the material that is not used for wood sanding is Emery