# How to Measure Force

1. May 9, 2010

### Zirok

Hi

In my shop, i have to design a fixture & want to calculate the force exerted by a moving element.

Can anyone let me know the simpliest formula to calculate force ?

Zirok

2. May 9, 2010

### Kracatoan

I would use the Kinetic Energy Equation - Ke = 0.5 * mass * velocity^2

This gives you the N per m^2 the object will exert if its hits something.

3. May 9, 2010

### tiny-tim

Welcome to PF!

Hi Zirok! Welcome to PF!

Force isn't necessarily the important issue.

Can you be more specific about what this fixture is, and why you're worrying about it hitting something?

4. May 22, 2010

### Zirok

Actually its a slider mechanism.

Slider weighing 1 kg is been loaded by a spring mechanism. To deisgn spring,I am concerned about what amount of force & what travel will be involved so as to design the spring accordingly.

Thanks
Zirok.

5. May 22, 2010

### Gordianus

I don´t understand the system. Could you please eleborate?

6. May 22, 2010

### tiny-tim

Hi Zirok!

The extension of the spring is proportional to the force exerted by the spring (which is the same as the tension or compression in the spring).

"Extension" means the difference between the "relaxed" length of the spring and its actual length under force.

So if the "relaxed" length is a, and you exert a force F on it, so that the length changes to a + x (x will be negative if the force is "inwards"), then F = kx, where k is the spring constant for this particular spring.​

(If the spring doesn't come with a spring constant marked on it, you can find it by testing it with some known weights … lay the spring horizontally on a table, and attach known weights to it on the end of a string running over the end of the table)

7. May 22, 2010

Hm...