A block and tackle pulley system on which an effort of W newtons supports a load of 120.0N,if the efficiency of the system is 40%,then what is the value of W?

E=m.a/v.r × 100%
Tackle and pulley syst with 6 pulleys gives the v.r as 6
40=m.a×100%/v.r
M.a= 6×40/100=2.4
But m.a=L/E i.e, 2.4=120N/E
E =120/2.4= 50N
Nb: i used 6 as my no. of pulleys. If u use another number u get another result.

Legendforte:
E=m.a/v.r × 100%
Tackle and pulley syst with 6 pulleys gives the v.r as 6
40=m.a×100%/v.r
M.a= 6×40/100=2.4
But m.a=L/E i.e, 2.4=120N/E
E =120/2.4= 50N
Nb: i used 6 as my no. of pulleys. If u use another number u get another result.

I respect u sir,50 is the answer but they didn’t give working

PrinceMike24:
I respect u sir,50 is the answer but they didn’t give working

Alright then