1. Torque and Statics
And you

2. “Give me a lever long enough and I shall move the world”!
Attributed to Archimedes
But what does it really mean man?
A lever provides you with a mechanical advantage
The longer the lever, the greater the mechanical advantage (as long as the lever does not break!)

3. How does it apply to our life????
Every time you move you are using a lever system
Doors
Wrenches
Anything with a pivot point and an a applied force that is perpendicular to the rotational axis or

4. You can calculate the magnitude of the torque by using the relationship:
Torque = (Force applied) x (distance from pivot point)
pivot - +
F = mg
F = mg
pivot

5. When there is a pivot point….
You need to consider the magnitude of the force that is being applied
And the distance of the applied force to the pivot point
The Force x distance = torque
Note that if you increase the distance you increase the torque
Hence: “give me a lever long enough and I will move the world”

6. If you are trying to achieve a balance on either side of the pivot (like in this the lab)
Then the torques on either side must be equal.
Now work on the lab and compare the torque on side A to the torque on side B – with a percent error calculation – for each situation (just the first measure of each situation)

7. Mini investigation Work with 1 partner (2 max) Use the levers provided
Use the provided balance blocks (with nails)
Use 2 large masses – and several washers
Investigate the effect of changing pivot point locations

8. Situation 1: use the pivot point #1 Place “mass A” at the end of the ruler so the opposite end of the ruler rises – then use a “mass B” to balance the ruler
Measure the distance from the “mass A” to the pivot point (nail) and record
Record “mass B” in kg
Measure the distance from the “mass B” to the pivot point (nail) and record
This ”mass A) stays at the end for all of your investigation – record this mass in Kg
Force of mass down = mg *mass in kg
Force of balancing force down = mg A B
Move this mass to establish balance
Distance to mass
Distance to balancing force

9. Situation 2: Keep “mass A” at the end of the ruler –and use pivot point #2 (in the middle)
Measure the distance from the “mass A” to the pivot point (nail)
Record “mass B” in kg
Measure the distance from the “mass B” to the pivot point (nail) and record
This “mass A” stays at the end for all of your investigation
Force of mass down = mg *mass in kg
Force of balancing force down = mg A B
Move this weight to establish balance – you may
need to change the “mass B” from situation 1
Distance to mass
Distance to balancing force

10. Situation 3: Keep “mass A” at the end of the ruler –and use pivot point #3
This “mass A” stays at the end for all of your investigation
Measure the distance from the “mass A” to the pivot point (nail)
Record “mass B” in kg
Measure the distance from the “mass B” to the pivot point (nail)
Force of mass down = mg *mass in kg
Force of balancing force down = mg A B
Move this weight to establish balance – you may
Need to change this mass from the previous
situations
Distance to mass
Distance to balancing force

11. Data table: Balanced Forces and masses
Distance mass (A) Force mass (A) F x dist. (A) distance mass (B) F mass (B) F x dist. (B)
to pivot point (m) (N = mg) (Nm) to pivot point (m) (N = mg) (Nm)
Note the calculated Force (from a mass) is calculated my multiplying the Mass (in kg) by 9.8 m/s2 = Force in Newton’s 1 2 3

12. One report for the group of 2 (with names and period)
Title
Objective
Diagram of set-up
data table
Full sentence answers to questions
Percent error calculation for each situation

13. Question A:
Situation 1) Did (Force A) (distance A) = (Force B) (distance B)
If not, by what percent was the measure off?
(Force A) (distance A) – (Force B) (distance B) x 100
(Force A) (distance A)

14. Question B:
Situation 2) Did (Force A) (distance A) = (Force B) (distance B)
If not, by what percent was the measure off?
(Force A) (distance A) – (Force B) (distance B) x 100
(Force A) (distance A)

15. Question C:
Situation 3) Did (Force A) (distance A) = (Force B) (distance B)
If not, by what percent was the measure off?
(Force A) (distance A) – (Force B) (distance B) x 100
(Force A) (distance A)

16. Question D:
If (Force A) (distance A) did not = (Force B) (distance B), then why do you think the values were different?
What would you need to consider to make
(Force A) (distance A) = (Force B) (distance B) a true statement in all situations?