Question

Two masses of 5kg and 2kg are connected by a rope.

the mass experiences a kinetic friction of 9.8N between it and the table. detemine the accelarition of the system. tension in the rope

Answer 1

If the 5 kg mass is on the table and the 3 kg mass is hanging connected to the 5 kg mass by a rope over a pulley, we can write the following equations:

$$5\text{ kg:}\space Ma=-f+T\\ 2\text{ kg:}\space -ma=T-mg,\\\space\\ a=\frac{mg-f}{m+M}=\frac{2·9.8-9.8}{2+5} =1.4\text{ m/s}^2,\\\space\\ T=m(g-a)=16.8\text{ N}.$$