billiards said:yo, i dunno. if you got hooke's law in one dimension then spose you got to just treat as a one dimensional problemo. it's just a constant of proportionality that links stress and strain.
the fact is if they were going to be nasty they'd give you some kind of anisotropy to deal with, which they haven@t (i assume) so you can deal with it as you find it!
fyzikschik said:so then i should just ignore the fact that this spring is inclined and stretched at an angle and at a a fixed distance and just say that since f=kx therefore k=mg/x ...right?
Since the spring is stretched parallel to the incline, you need to consider the force on it parallel to the incline.fyzikschik said:how would you find the k (N/m) of a spring that is inclined at an angle (for ex. 30degrees)? Do you just ignore the fact that it's inclided at an angle? By the way, the spring is stretched at 8cm.
Consider the forces on the mass attached to the spring parallel to the incline. Potential energy is not a force.Would the forces acting on the spring in this case be force of gravity at 30deg an potential energy ( Ee=1/2 kx^2 ).
Wrong. The angle of the incline determines the force that stretches the spring. (Imagine if the angle of incline were 0 degrees--horizontal--or 90 degrees--vertical. Big difference, right?) Consider the forces acting on the attached mass parallel to the incline.fyzikschik said:so then i should just ignore the fact that this spring is inclined and stretched at an angle and at a a fixed distance and just say that since f=kx therefore k=mg/x ...right?
Doc Al said:Since the spring is stretched parallel to the incline, you need to consider the force on it parallel to the incline.
Consider the forces on the mass attached to the spring parallel to the incline. Potential energy is not a force.
Wrong. The angle of the incline determines the force that stretches the spring. (Imagine if the angle of incline were 0 degrees--horizontal--or 90 degrees--vertical. Big difference, right?) Consider the forces acting on the attached mass parallel to the incline.
Your above answer is correct. The normal reaction force does not affect the tension in the spring since it acts perpendicular to the spring. With respect to your next question, not the spring constant remains constant. Although by altering the angle you are varying the force applied to the spring, the spring will extend by an amount equal to x = F/k. This is why it is called the spring constant. It is constant. To verify this, you could try varying the angle of the incline and noting the extension produced in the spring.fyzikschik said:I guess my real question now is, do I have to attach a mass to this spring and measure the k at the angle? Would the k be the same if I hung the spring vertically with the same mass at a 90 degree angle? Because I'm confused as to whether the k changes if the spring is at an angle or to the vertical or horizontal!
The forces acting on the mass parallel to the incline are:fyzikschik said:ok, so the force would be gravity, k= m*sin30*9.8/x??
would force of tension be included?
The normal force will balance the perpendicular component of gravity. But that won't help you find k, so you don't need to worry about it.what about the normail force, because we are talking about the spring being in contact with the inclined launch pad
k is a property of the spring. I doesn't matter what the angle of incline is, the spring constant is the same. If you change the angle, both the sine of the angle and the amount of stretch will change together. The value of k that you find will be the same no matter what the angle. So if you've measured it once, that's enough.fyzikschik said:I guess my real question now is, do I have to attach a mass to this spring and measure the k at the angle? Would the k be the same if I hung the spring vertically with the same mass at a 90 degree angle? Because I'm confused as to whether the k changes if the spring is at an angle or to the vertical or horizontal!
Do you mean the tension in the spring. And yes you can ignore the normal force.fyzikschik said:so then, at an angle theta, k=*m*sintheta*9.8/x ??
i'm assuming we can discard the force of tension and the normal force (since they are perpendicular)
I never said anything about the mass of the spring. I thought you were asking about how to measure the spring constant of a (presumably massless) spring by hanging a mass off one end. If the spring constant is high enough (in other words, if the spring is stiff enough) you can neglect the mass of the spring in measuring its spring constant.fyzikschik said:i'm assuiming (and according to doc al) that since the force constant is the same that i should just measure the mass of the spring, and say (k=m*g*x).
K; the force constant of a spring, also known as the spring constant, is a measure of the stiffness of a spring. It represents the amount of force required to stretch or compress a spring by a certain distance.
The force constant of a spring can be calculated by dividing the force applied to the spring by the displacement of the spring from its equilibrium position. This can be represented by the equation K = F/x, where K is the force constant, F is the applied force, and x is the displacement of the spring.
The units of the force constant depend on the units used for force and displacement. In the SI system, the force constant is measured in Newtons per meter (N/m). In the English system, it is measured in pounds per inch (lb/in).
The force constant determines the strength and properties of a spring. A higher force constant indicates a stiffer spring, meaning it requires more force to stretch or compress it by a certain distance. A lower force constant indicates a more flexible spring, meaning it requires less force to deform it.
The period of oscillation of a spring is directly proportional to the force constant. This means that a higher force constant will result in a shorter period of oscillation and vice versa. This relationship is represented by the equation T = 2π√(m/K), where T is the period, m is the mass attached to the spring, and K is the force constant.