When a jet of water strikes the vane of water turbine and is deflected through the angle "theta", the force on the vane varies directly as the square of the jet velocity and the sine of theta/2. If "theta"is decreased from 55 degrees to 40degrees, and if the jet velocity increases by 40%, by what % will the force change?

F =k*v^2*sin(theta/2).

F1=k*v^2 sin 55.

F2=k*1.4v^2*sin 40.

F1/F2=sin 55/(1.4* sin 40).

=0.91.

F2=F1/0.91.

=1.1F1.

Force increases by 10%.