F x d1= R x d2

LAW OF THE LEVER (OR LEVER’S LAW)

The lever is balanced when the effort F, multiplied by its distance, d1 is equal to the load R, multiplied by its distance from the fulcrum, d2.

This is called the Law of the Lever

F= force (in newtons, N)

R = load or resistance (in newtons, N)

d1= distance from the fulcrum to the force (in meters, m)

d2=distance from the fulcrum to the resistance (in meters, m)

EXERCISES:

Use your dictionary to learn new words.

1. You have a first lever class and here you have the data:

Distance from the fulcrum to the load 3 meters Distance from the fulcrum to the effort 5 meters Load 1000 N

Calculate the effort F, you have to do to balance that load.

Draw the lever.

F???

R= 1000 N

d2= 3 m F * d1= R * d2 (F = x)

d1=5 m F= x= (R* d2)/ d1

F= (1000* 3)/ 5

F= 600 N

2. How far from the fulcrum of a seesaw should a boy weighing 30 kg sit, if a girl at the other end who weights 20 kg, is sitting 2 m from the fulcrum? And if the girl is now sitting 4 m from the fulcrum? What conclusions can you write?

3. Write an exercise about the Lever’s Law. Solve the exercise and draw a drawing.

4. Draw and colour a fishing rod and indicate clearly the fulcrum, the load and the effort.

5. Explain with your own words THE LAW OF THE LEVER. Do a picture to explain it.