Can anyone help me with an Algebra 2 word problem?

Question

To use a lever you need something(between its two ends) to prop it against. That something is called a fulcrum.

Formula: (the weight you apply to your end)X(your distance from the fulcrum)=(the weight you can move at the other end)X(its distance from the fulcrum)

Now suppose you have a four-foot crowbar and want to move a 300 pound rock.
What is the greatest distance from the rock the fulcrum can be placed if you are able to apply weight of:
a) 50 pounds?
b) 100 pounds?
c) 150 pounds?


I would appreciate help with this. I'm sure it's easy but I have a brain fart at the moment. I don't just want answers, I want explinations please. I'm just not sure where to plug everything in at...and some other stuff. Please help...10 Points!!!!!!!!!!!1

Answer 1

This is basically called balancing moments in classical physics.

300(x) = (4-x)weight

where weight is as given above (50,100,150).

Basically if you place the fulcum at a point, then your counterweight (300) is exactly that far from the fulcrum. Because the lever is 4 feet long the length opposite the fulcrum is exactly (4-x).

QED

Answer 2

a. 150=1000
b. 300=2000
c. 450=3000

hope these are correct