A printed circuit board (PCB) is supported by a chassis that is attached to a vibrating motor. The board is 1.6 mm thick, 200 mm
1 answer:
You might be interested in
The new cross sectional area and tensile stress is mathematically given as
A=4.8*10^{-4}m^2
X=14:100
<h3>Cross sectional area and stress on the femur</h3>Question Parameters:
To see why this must be so, recall, that the stress on the femur for a man standing on one leg is 1.4%
we scale this man up by a factor of 10 in all dimensions
that a 70 kg person has a femur with a cross-section area
a)
Generally the New cross sectional area is mathematically given as
100A=100*4.8*10^{-4}
A=4.8*10^{-4}m^2
b)
From the initial statement we see that the fraction of the tensile strength is the stress on the femur and will be
X=14$
X=14:100
For more information on fraction
Complete Question
Larger animals have sturdier bones than smaller animals. A mouse's skeleton is only a few percent of its body weight, compared to 16% for an elephant. To see why this must be so, recall, that the stress on the femur for a man standing on one leg is 1.4% of the bone's tensile strength. Suppose we scale this man up by a factor of 10 in all dimensions, keeping the same body proportions. (Assume that a 70 kg person has a femur with a cross-section area (of the cortical bone) of 4.8 x 10-4m², a typical value.)
Part A
Both the inside and outside diameter of the femur, the region of cortical bone, will increase by a factor of 10. What will be the new cross-section area? Express your answer using two significant figures.
Part B
If the scaled-up man now stands on one leg, what fraction of the tensile strength is the stress on the femur?
Answer:
505.62 mm
Explanation:
Young's modulus of a material is given by,
Stress is the force experienced by the material per unit area (which is why stress has the same units as pressure).
Strain is the ratio between the change in length/area/volume to the original length/area/volume of the material (and hence a dimensionless quantity). Basically, it gives us a measure of the change in dimensions due to the stress experienced.
So, for the given problem,
or, (since we need to find the compression of the bone at the critical stress point)
or,