$1.$ a$.)$ Determine the torque $($N$-$m$)$ produced at Pulley $4$ if the force at Pulley $1=300$kg$,$ given that Pulley $1=4$ inches in diameter, Pulley $2=10$ inches, Pulley $3=3$ inches, Pulley $4=12$ inches. If Pulley $1$rotates at $3500$ RPM$.$

b$.)$ What is the power produced at Pulley $4,$if the transmission efficiency of the system is only $89\%?$