A 5-m-long steel cable is horizontally attached (just tautly) between two large trees. A 40-kg child hangs from the middle, and in doing so lowers the cable 6 cm from its original position. The tension in the cable is
A) 400 N.
B) 4400 N.
C) 8200 N.
D) 800 N.

Question

Quizplus · Accepted Answer

The tension in the cable is equal to the weight of the child, which is 400 N. The cable is lowered by 6 cm, which means that the tension in the cable is doing work against gravity. The work done is equal to the force times the distance, which is 400 N times 0.06 m, or 24 J. The tension in the cable is therefore 8200 N.

A 5-M-Long Steel Cable Is Horizontally Attached (Just Tautly) Between