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3 years ago

Intro to Springs and Hooke’s law

1 answer:

wel3 years ago

6 0

A spring is an object that can be deformed by a force and then return to its original shape after the force is removed.
Springs come in a huge variety of different forms, but the simple metal coil spring is probably the most familiar. Springs are an essential part of almost all moderately complex mechanical devices; from ball-point pens to racing car engines.
There is nothing particularly magical about the shape of a coil spring that makes it behave like a spring. The 'springiness', or more correctly, the elasticity is a fundamental property of the wire that the spring is made from. A long straight metal wire also has the ability to ‘spring back’ following a stretching or twisting action. Winding the wire into a spring just allows us to exploit the properties of a long piece of wire in a small space. This is much more convenient for building mechanical devices.

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Non example of a Mass Number

Zielflug [23.3K]

Are there any options or is it not a multiple choice question.

4 0

4 years ago

Water is flowing through a 45° reducing pipe bend at a rate of 200 gpm and exits into the atmosphere (P2 = 0 psig). The inlet to

Nataliya [291]

Answer:

F1=177.88 Newtons

Explanation:

Let's start with the Bernoulli's equation:

$P_{1} + \frac{1}{2}\beta V_{1} ^{2} + \beta gh_{1} =P_{2} + \frac{1}{2}\beta V_{2} ^{2} + \beta gh_{2}$

Where:

P is pressure, V is Velocity, g is gravity, h is height and β is density (for water β=1000 kg/m3); at the points 1 and 2 respectively.

From the Bernoulli's equation and assuming that h is constant and P2 is zero (from the data), we have:

$P_{1} + \frac{1}{2}\beta V_{1} ^{2} = \frac{1}{2}\beta V_{2} ^{2}$

As we know, P1 must be equal to $\frac{F_{1} }{A_{1}}$ , so, replacing P1 in the equation, we have:

$P_{1} = \frac{F_{1}}{A_{1}} = \frac{1}{2}\beta(V_{2} ^{2} - V_{1} ^{2})$

And

$F_{1} = {A_{1}} ( \frac{1}{2}\beta(V_{2} ^{2} - V_{1} ^{2}))$

Now, let's find the velocity to replace the values on the expression:

We can express the flow in function of velocity and area as $Q = V A$ , where Q is flow, V is velocity and A is area. As the same, we can write this: $Q_{1} = V_{1} A_{1}\\Q_{2} = V_{2} A_{2}$ . In the last two equations, let's clear Velocities.

$V_{1} = \frac{Q_{1}}{A_{1}}\\V_{2} = \frac{Q_{2}}{A_{2}}$

and replacing V1 and V2 on the last equation resulting from Bernoulli's (the one that has the force on it):

$F_{1} = {A_{1}} ( \frac{1}{2}\beta((\frac{Q_{2}}{A_{2}})^{2} - (\frac{Q_{1}}{A_{1}})^{2}))$

First, we have to consider that from a mass balance, the flow is the same, so Q1=Q2, what changes, is the velocity. Knowing this, let's write the areas, diameters, density and flow on International Units System (S.I.), because the exercise is asking us the answer in Newtons.

$D_{1}=1.5 inches=0.0381 mts\\D_{2}=1 inches=0.0254 mts\\A_{1}=\frac{\pi D_{1}^{2} }{4}=0.00114mts^{2}\\A_{2}=\frac{\pi D_{2}^{2} }{4}=0.000507mts^{2}\\\beta=1000 kgs/m^{3}\\Q=200gpm=0.01mts^{3}/seg$

Replacing the respective values in this last expression, we obtain:

F1 = 177.88 N

3 0

3 years ago

If the tensile strength of the Kevlar 49 fibers is 0.550 x 106 psi and that of epoxy resin is 11.0 x103 psi, calculate the stren

Elina [12.6K]

Answer:

$\sigma_{tot} =436810 psi$

Explanation:

Notation

$\sigma_{fib} =0.55x10^6 psi$ represent the tensile strength for the Kevlar 49 fibers

$\sigma_{epox} =11x10^3 psi$ represent the tensile strength for the epoxy resin

79% by volume is made of Kevlar 49 fibers

The rest 100-79=21% is made of epoxy resin

Tensile strength is a "measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks". Can be defined as "the maximum amount of tensile stress that it can take before failure".

For this case we need to use a basis of calculus since we don't know the total volume but we can assume a reference value on order to make the calculations.

If we assume a total volume of $V_{tot}=1 in^3$ we can do the follwoing balance:

$\sigma_{tot}V_{tot}=\sigma_{fib}V_{fib} +\sigma_{epox}V_{epox}$

We can replace the values given:

$\sigma_{tot}=(0.55x10^6 psi)(0.79) +(11x10^3 psi)(1-0.79)$

$\sigma_{tot} =436810 psi$

So then the strength of the composite material is : $\sigma_{tot} =436810 psi$

4 0

4 years ago

What is the best definition of muscular strength

BabaBlast [244]

Answer:

Muscular strength is defined as the maximum amount of force that a muscle can exert against some form of resistance in a single effort. ... In the gym, a single repetition at a given weight is an example of muscular strength.

Explanation:

6 0

4 years ago

The weight of a girl on the Earth is 340 N, what is her mass on Earth?(g= 10Nkg-1)

kirill [66]

Answer:

34 kg is the answer to the question

4 0

3 years ago