A string is attached to the rear-view mirror of a car. A ball is ...

[Coya19@aol.com]

A string is attached to the rear-view mirror of a car. A ball is hanging at the other end of the string. The car is driving around in a circle, at a constant speed. Which of the following lists gives all of the forces directly acting on the ball?
 
  A) tension and gravity
  B) tension
  C) tension, gravity, and the centripetal force
  D) tension, gravity, the centripetal force, and friction

Question 2

Block A of mass 8.0 kg and block X are attached to a rope that passes over a pulley. A 50-N force P is applied horizontally to block A, keeping it in contact with a rough vertical face.
 
  The coefficients of static and kinetic friction between the wall and block A are s = 0.40 and k = 0.30. The pulley is light and frictionless. In the figure, the mass of block X is adjusted until block A descends at constant velocity of 4.75 cm/s when it is set into motion. What is the mass of block X?
 
  A) 6.5 kg
  B) 7.2 kg
  C) 8.0 kg
  D) 8.8 kg
  E) 9.5 kg

[ynlevi]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: A

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