A 3.00-m long plank of negligible mass has a 30.0-kg mass at one ...

[cagreen833]

A 3.00-m long plank of negligible mass has a 30.0-kg mass at one end and a 40.0-kg mass at the other end. How far from the 30.0-kg mass should a fulcrum be placed so that the plank is balanced?
 
  A)
 
  1.71 m
 
  B)
 
  1.29 m
 
  C)
 
  0.750 m
 
  D)
 
  1.50 m
 
  E)
 
  2.25 m

Question 2

State the principle of conservation of mechanical energy
 
  What will be an ideal response?

[lkoler]

Answer to Question 1

A

Answer to Question 2

If only conservative forces are doing work, the total mechanical energy of a system neither increases nor decreases in any process. It stays constant - it is conserved.