Question 13

A 2 kg mass rests on a rough plane and is attached to an unstretched spring with a spring constant of 50 N/m. A 10 kg mass is attached to the 2 kg mass by means of a cord passing over a pulley. The 10 kg mass is released from point "A" and in falling to point "B" increases its speed from zero to 1.5 m/s.
(Neglect the mass of the cord and spring in the following questions.)

Show the reasoning in arriving at your answers to these questions in your notebook.
Let g = 10 m/s² .

A. What is kinetic energy of the 10 kg mass at point "B"?	Answer.
B. What is kinetic energy of the 2 kg mass when the 10 kg mass reaches point "B"?	Answer.
C. What is the change in gravitational potential energy of the 10 kg mass?	Answer.
D. What is the change in the potential energy of the spring as the 10 kg mass moves from point "A" to point "B"?	Answer.
E. How much of the system's mechanical energy is converted into heat as 10 kg mass falls from "A" to "B"?	Answer.
F. What is the average friction force acting on the 2 kg mass?	Answer.

Formula Sheet

Question 12

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