A 1.20-kg ball is hanging on the end of a rope. The rope makes an ...

[Yi-Chen]

A 1.20-kg ball is hanging on the end of a rope. The rope makes an angle 25.0 from the vertical when a 15.0 m/s horizontal wind blows. If the wind's force on the rope is negligible, what is the drag force on the ball?
 
  A)
 
  32.3 N
 
  B)
 
  24.1 N
 
  C)
 
  3.68 N
 
  D)
 
  5.49 N
 
  E)
 
  11.8 N

Question 2

A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her angular speed increases dramatically. The speed increase is a demonstration of
 
  A)
 
  conservation of kinetic energy: her moment of inertia is decreased, and so her angular speed must increase to conserve energy.
  B)
 
  conservation of total energy: her moment of inertia is decreased, and so her angular speed must increase to conserve energy.
  C)
 
  conservation of angular momentum: her moment of inertia is decreased, and so her angular speed must increase to conserve angular momentum.
  D)
 
  Newton's second law for rotational motion: she exerts a torque and so her angular speed increases.
  E)
 
  This has nothing to do with mechanics, it is simply a result of her natural ability to perform.

[Dnite]

Answer to Question 1

D

Answer to Question 2

C

[Yi-Chen]

TYSM

[nanny]

Excellent