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Definition;

Momentum = jisim x halaju = mv

Units: kg m/s

Each particle in the fluid stream has momentum.

Whenever the velocity of the stream changes,

magnitude or direction, the momentum of particlechanges.

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Whenever a jet of liquid

impinges on a fixed plate,it experiences some

force.

As per Newton's Second

Law of Motion, this force

is equal to the rate ofchange of momentum of

the jet. It has been

observed that if the plate

is not fixed, then the

plate starts moving in the

direction of the jet,

because of the force.

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Newtons 2nd Law:

A force is required to produce a change in

momentum.

This may be provided by contact with solid

boundary or by one part of the fluid stream

acting on another.

This may be expressed as:

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Consider a jet of water impinging normally on a fixed plate as shown in fig-1.

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A jet of water of 100 mm diameter impinges normally on a fixed plate

with a velocity of 30 m/s. Find the force exerted on the plate.

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A jet of water 50 mm diameter is discharging under a

constant head of 70 metres. Find the force by the jeton a fixed plate. Take coefficient velocity as 0.9

(2.19 kN)

A horizontal jet of water is issuing under an effective

head of 25 m. Calculate the diameter of the jet, if the

force exerted by the jet on a vertical fixed plate is

2.22 kN. Take Cv = 1.(75 mm)

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A jet of water of 10 cm diameter impinges normally on

a fixed plate with velocity of 20 m/s. Find the forceexerted on the plate.

(3141.6 N)

A jet of water of 10cm diameter is discharging under a

constant head of 100m. Find the force exerted by the

jet on a fixed plate. Take coefficient of velocity 0.9.(12477 N)

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Seorang pekerja menyemburkan air ke dinding

bangunan menggunakan hos. Nosel hos menghasilkanjet berdiameter 15 cm dengan halaju 1.5 m/s. Kira

daya hentaman jet terhadap dinding jika jet dinding

bersudut tepat dan tiada lantunan jet ketika itu.(39.761 N)

Jet air yang berdiameter 100 mm dikenakan ke atas

plat tegak dengan halaju 30 m/s. Cari daya hentamanjet ke atas plat tersebut.

(7068.583 N)

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Consider a jet of water impinging normally on a fixed plate as shown in fig-1.