Masses m₁ = 5 kg and m₂ = 10 kg are connected over a frictionless pulley and are already moving as shown. The coefficient of friction of the horizontal surface is 0.15. What minimum mass m should be placed on m₂ to stop the motion?

Question

G1 Physics · Accepted Answer

For the motion to be retarded, friction on m₂ must be large enough that the acceleration reverses relative to the shown motion. The threshold is about 23.3 kg; among the given choices the smallest mass that certainly makes the acceleration oppose the motion is 27.3 kg. Hence option A, matching the source key.