Multiple Choice
Energy conservation with nonconservative forces: An 0.80-kg block is held in place against the spring by a 67-N horizontal external force (see the figure) . The external force is removed, and the block is projected with a velocity v1 = 1.2 m/s upon separation from the spring. The block descends a ramp and has a velocity v2 = 1.9 m/s at the bottom. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction over this section is 0.39. The velocity of the block is v3 = 1.4 m/s at C. The block moves on to D, where it stops. The spring constant of the spring is closest to 
A) 3900 N/m.
B) 2600 N/m.
C) 2000 N/m.
D) 1600 N/m.
E) 1100 N/m.
Correct Answer:

Verified
Correct Answer:
Verified
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