Advice 1: How to find the spring stiffness

In physics the term "spring rate" is more accurately the stiffness coefficient of the spring. To determine experimentally the spring stiffness, you need to know Hooke's law: F=|kx|. To calculate the desired quantities it is necessary to measure the other two and then using the laws of mathematics, to solve an equation with one unknown.
How to find the spring stiffness
You will need
  • spring any a weight of 100 grams, ruler
It should vertically to fasten the spring. Measure with a ruler the length of the spring before it hang the cargo during the suspension of weight on it. Calculate the difference of the lengths of the springs. It turns out that x = x1-x2, found elongation of the spring.
Mounted on the spring any a weight of 100 grams. This weight acts on the spring with a force equal to 1 Newton. Therefore, the second value is already known. F= 1N.
According to Hooke's law to find the stiffness coefficient of the spring, it is necessary to divide the tensile force of a spring on its lengthening. k=F/x. These two values are already defined empirically.
The ruler measures the elongation in inches, if you apply the value found without translation to meters, you get the erroneous calculation of the stiffness of the spring.
Useful advice
1cm =0.01 m.
4 cm= 4*0,01 = 0,04 m.

Advice 2: How to determine spring stiffness

Spring is a component of the car's suspension, which protected the car from irregularities in the road, but also provide the desired height of the body above the road, which greatly affects the handling of the vehicle, comfort and payload capacity. As a result of the tests for each vehicle select the optimum stiffness of the suspension springs under certain traffic conditions.
How to determine spring stiffness
If you experience "breakdowns" suspension spring is too soft. In such situations, the drivers become unstable in control. Ideally, the spring force must be equal to the value that prevents excessive body roll.
Stiffer springs require the cars prepared for racing. In different types of races using the same car involves the installation of springs with different stiffnessYu. Pay attention when passing any corners for body roll that, when properly selected springs should be no more than two or three degrees.
For the front and rear suspension pick spring stiffness pairs. However, it is not immediately possible to achieve the desired height of the suspension, because the spring sits and at some point may "get lost" that's really bad. This is due to lack of bearing capacity, even at full compression, but with the stiffnesss, providing the necessary height of the suspension. This is determined always easy: between the spring windings should be a gap of less than 4 mm.
Choose the springs so that when refilled the car the gap between the turns of the springs was slightly more than 6.5 mm. it is Desirable to set the soft springs, even though they will give a roll of the machine within acceptable limits. To use stiff springs, based on the opinion that they reduce the roll of the car, improving handling, as a rule, incorrect.
Check the stiffness of the spring by a product code or for applying labels or stamping paint). Also determine the stiffness of the springs using the hand pump, floor scales and measuring line in kilograms per centimeter.
On everyday scales fit a piece of wood (thickness 12 mm) square at the larger end of the spring, and the top is a spring. Then, on the upper end of the spring is placed a second piece of wood is measured length of the spring. With a press of the spring compress to a certain size (e.g. 30 mm) and take readings of the weights, thereby computing the stiffness.
The pressure on the spring is measured according to the testimony of the weights, but this method of determining the stiffness of springs is dangerous as the spring can fly off at a sufficiently large distance.
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