finding out the hookes law constant?

Question

i need to know a method to find out hookes law constant..using a spring, metre ruler, masses and a retort stand..how would one do that??? :s please help

Answer 1

F = k(dx); where F is force, k is the Hooke's constant, and dx = x1 - x0 is a change in the length of the spring from its neutral position at x0 (that is x0 is the length of the spring without a weight/force attached). Thus, k = F/dx; so you can measure the force on a spring and the amount of extension (dx) under that force.

Recognize that each force can be the weight (W = F = mg) of those "masses" you are talking about. Two masses m and M, for example, can create forces f = mg and F = Mg. And they can be combined (m + M) to make a third data point. Measure the stretch under each weight using the ruler. Use g = 9.81 m/sec^2 when calculating each weight.

So you can measure the following data:

Data point 1: f, dx = x1 - x0; where x1 is the spring length under weight (f) and x0 is the length without the weight. Then k1 = f/(x1 - x0)

Data point 2: F, dX = x2 - x0; so that k2 = F/(x2 - x0)

Data point 3: (f + F), (dx + dX) = x3 - x0; so k3 = (f + F)/(x3 - x)

Take the sum(k) = k1 + k2 + k3 and divide by N(k) = 3 data points to get kavg = sum(k)/N(k). kavg, the average k, should be pretty close to the actual Hooke's constant of that spring. Your resulting average k should be even more accurate (less error of estimate) if you use more weight (forces) to create more data points.

There is another way to do this using graph paper and plotting force vs. stretch. Turns out, the slope of the straight line through the data points is k. But as you did not mention graphing, just do it the way it was described above.

Answer 2

Hang the spring vertically. If you know the mass, you can get the weight in Newtons (N) You attach the masses to the spring and measure by how much the spring stretches out.

Then We know by Hooke's Law F=kx

So k=F/x

Where F is the weight ofd the masses and x is the displacement length of the spring, and k is the Spring Constant (in N/m, N/cm, etc)

Answer 3

owen is correct for all but the "340N for obvious reasons" force he gave. it is a spring so the force will be actually 170N changing everything past that point.