Question is shown below?

• The following approaches has been used to solve the problem.
  1- air friction has been neglected.
  2- water's momentum has been conserved.
  3- water hitting the wall has been completely reflected.

• the velocity vector of the water changes because both the magnitude and the direction have changed.

• the velocity vector of water has been shown in figure below as red and blue respectively.

• the momentum vector of the water hitting to the wall and of the water reflected are shown in figure below.

• the changing of velocity causes a change of momentum of the water.

#"let the change in momentum vector be "Delta vec P#

#Delta vec P= vec P_a-vec P_b#

#"where "vec P_a " is momentum after hitting and "vec P_b" is "#

#"momentum before hitting the wall."#

#Delta vec P= -(2Kv_0)/3-Kv_0#

#Delta vec P=-(5Kv_0)/3#

• The momentum change vector is drawn as follows.

• The momentum change vector is perpendicular to the wall.

• The momentum change vector is at the negative direction.

• the directions have selected as randomly. You can change if you want.

• the magnitude of change of momentum is :

#Delta P=(5Kv_0)/3#

• if we accept momentum is conserved we can write as fallows.

#vec F* Delta t=Delta vec P#

#vec F* Delta t=(5Kv_0)/3#

#"if the interaction unit time is considered t = 1 sec"#

#F=(5Kv_0)/3 " Newtons."#