Simple machine 2

John wants to move a 400N. rock with a 5m. crowbar. He puts the fulcrum 0.9m from the rock. How much force must he use to move the rock?

STEP 1:

Let x = force used

In order for the above lever to be balanced, the following equation must be satisfied.

w1 × d1 = w2 × d2

Step 2: Sketch the diagram

Step 3: Obtain equation from the diagram

9 × 400 = 60 × x

A See-Saw is 25 feet long with a fulcrum in the middle of the board. If a 60 lb. child sits three feet from the fulcrum, where must a 100 lb. child sit to balance the 60 lb.

Formula

w1d1=w2d2