A playground merry-go-round with a radius of 2.0 m and a ...

[pragya sharda]

A playground merry-go-round with a radius of 2.0 m and a rotational inertia of 100 kg m2 is rotating at 3.0 rad/s.
 
  A child with a mass of 22 kg jumps onto the edge of the merry-go-round, traveling radially inward. What is the new angular speed of the merry-go-round?
  A)
 
  1.6 rad/s
 
  B)
 
  1.2 rad/s
 
  C)
 
  2.4 rad/s
 
  D)
 
  2.0 rad/s
 
  E)
 
  3.4 rad/s

Question 2

Calculate the radius that a loop should have so that the magnetic energy density at its center is equal to 6 mJ/ m3 when a current I = 20A passes through the loop?
 
  A)
 
  26 cm
  B)
 
  10 cm
  C)
 
  7 cm
  D)
 
  18 cm
  E)
 
  15 cm

[aruss1303]

Answer to Question 1

A

Answer to Question 2

B

[pragya sharda]

Excellent

[Perkypinki]

Gracias!