A stream of water strikes a stationary turbine blade. The incident water stream has a velocity of +18.0 m/s and the exiting stream has a velocity of –18.0 m/s. The water strikes the blade at a rate of 25.0 kg/s. Find the net force acting on the water and on the blade.

Answer 1

assuming the incident and exiting streams are 180 degrees, net change in velocityis 36m/s
force=impulse/time= mass/time*change velociyt=25kg/s*36m/s
remember that force= kg-m/s^2
force=36*25 N

Answer 2

Im not sure I understand. The book gives me two different answers, one is negative one is positive

please explain