Two blocks of masses 22 kg and 9 kg are connected together by a light string and rest on a frictionless level surface.Attached to the 9-kg mass is another light string,which a person uses to pull both blocks horizontally.If the two-block system accelerates at 0.7 m/s²,what is the tension in the second string attached to the 8-kg mass? A) 21.7 N B) 9.1 N C) 15.4 N D) 6.3 N E) 31 N

Question

Quizplus · Accepted Answer

The tension in the second string is equal to the force applied by the person minus the force of friction between the blocks and the surface. The force of friction is equal to the coefficient of friction times the normal force, which is equal to the weight of the blocks. The coefficient of friction is zero, so the force of friction is zero. Therefore, the tension in the second string is equal to the force applied by the person, which is equal to the mass of the blocks times the acceleration. The mass of the blocks is 22 kg + 9 kg = 31 kg, and the acceleration is 0.7 m/s^2, so the tension in the second string is 31 kg * 0.7 m/s^2 = 21.7 N.

Two Blocks of Masses 22 Kg and 9 Kg Are