A uniform beam with a mass of 120 kg and a length of 5.0 m rests ...

[armygirl]

A uniform beam with a mass of 120 kg and a length of 5.0 m rests on two supports, one at the left edge and one 3.0 m from the left edge. How close to the right edge can a 68-kg person walk along the beam without causing it to tip over?
 
  A)
 
  1.6 m
 
  B)
 
  1.8 m
 
  C)
 
  0.88 m
 
  D)
 
  1.5 m
 
  E)
 
  0.50 m

Question 2

The electric field along the axis of a ring-shaped charge of total charge Q distributed uniformly is given by E = Qx/(4 0 (x2+ a2)3/2 )
 
  where a is the radius of the ring and x is the distance from the center of the ring. The electric field at the center of the ring is zero and at great distances from the ring approaches zero. At what position is the electric field a maximum for positive values of x?

[lin77x]

Answer to Question 1

A

Answer to Question 2

x = 0.707 a

[armygirl]

Excellent

[Dnite]

Gracias!