Three blocks of masses 2 kg, 3 kg and 5 kg form a system on a smooth horizontal surface. External horizontal forces of 40 N to the right and 10 N to the left act on the system. If the acceleration of the centre of mass is N m/s², find N.

Question

G1 Physics · Accepted Answer

The net external horizontal force on the system is F(ext) = 40−10 = 30 N to the right. Total mass M = 2+3+5 = 10 kg. Newton's second law for the complete system gives F(ext) = M a(CM). Therefore a(CM) = 30/10 = 3 m/s². Hence N = 3.