A 3.0-kg block moves up a 40° incline with constant speed under the action of a 26-N force acting up and parallel to the incline. What magnitude force must act up and parallel to the incline for the block to move down the incline at constant velocity?
A. 14 N
B. 12 N
C. 16 N
D. 18 N
E. 25 N
Answer: B
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