Question 81
Calculating moments
In this investigation, you will investigate how the force needed to turn an object varies with distance from the pivot. Work in groups of two or three.
You will need: metre rule; forcemeter; two clamp stands; elastic (rubber) band; ruler; string; sticky tape; G-clamp. Set up the apparatus as shown in the diagram.
Method
1. Move the loop of string with the forcemeter as far from the pivot as you can.
2. Record the distance between the pivot and the forcemeter.
3. Raise the forcemeter so it is not pulling down on the metre rule.
4. Use the forcemeter to pull down on the metre rule. The distance that you pull depends on the strength of the elastic band. The metre rule needs to be pulled down far enough to get a reading of about 1 N at the furthest point from the pivot.
5. Use the ruler to record the distance that the metre rule moves. This will be the distance the metre rule should be pulled down each time.
6. Record the force.
7. Repeat this, pulling the metre rule down the same distance each time. Each time, use the loop of string to move the forcemeter closer to the pivot.
8. Your results should be a set of distances and forces.
9. Decide whether you need to repeat any of your measurements.
Explain the pattern in your results.
In this investigation, you will investigate how the force needed to turn an object varies with distance from the pivot. Work in groups of two or three.
You will need: metre rule; forcemeter; two clamp stands; elastic (rubber) band; ruler; string; sticky tape; G-clamp. Set up the apparatus as shown in the diagram.
Method
1. Move the loop of string with the forcemeter as far from the pivot as you can.
2. Record the distance between the pivot and the forcemeter.
3. Raise the forcemeter so it is not pulling down on the metre rule.
4. Use the forcemeter to pull down on the metre rule. The distance that you pull depends on the strength of the elastic band. The metre rule needs to be pulled down far enough to get a reading of about 1 N at the furthest point from the pivot.
5. Use the ruler to record the distance that the metre rule moves. This will be the distance the metre rule should be pulled down each time.
6. Record the force.
7. Repeat this, pulling the metre rule down the same distance each time. Each time, use the loop of string to move the forcemeter closer to the pivot.
8. Your results should be a set of distances and forces.
9. Decide whether you need to repeat any of your measurements.
Explain the pattern in your results.
