Question is shown below?

enter image source here

1 Answer
Feb 20, 2018

#"please have a look at the fallowing explanations."#

Explanation:

  • 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.

enter image source here

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

enter image source here

  • 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.

enter image source here

  • 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."#