Question

Please Answer Q:12. The answer is 70N but I don't know how did it come. So please answer with adequate steps.
(If you think opt.A is wrong then you can correct me with proper steps).

Answer 1

Answer:

HI

ON WHOLE SYSTEM F =60

M=20KG AND A=F/M =3m/s^2

so on first 6 kg block f is

100-4a=6a

a=10m/s^2

so THE ROPE WILL EXERT A FORCE OF 4* 10 ON 10 KG BLOCK

F=40N .

HOPE IT HELPS