Supose the water flows out from a pipe at 3 kg/s & its velocity changs from 5 to 0 on striking wall then the force exrted by water on wall wil be?
15N
15N
Since the mass flow rate is 3 kg/s and the velocity changes from 5 to 0 m/s, the force exerted by the water on the wall can be calculated as:
Force = (mass flow rate) x (velocity change)
Force = 3 kg/s x 5 m/s
Force = 15 N
So the force exerted by the water on the wall is 15 Newtons.
To find the force exerted by the water on the wall, we need to use the principle of conservation of momentum. Momentum is the product of mass and velocity.
First, we calculate the initial momentum of the water:
Initial momentum = mass × initial velocity
= 3 kg/s × 5 m/s
= 15 kg·m/s
Next, we calculate the final momentum of the water:
Final momentum = mass × final velocity
= 3 kg/s × 0 m/s
= 0 kg·m/s
According to the principle of conservation of momentum, the change in momentum of an object is equal to the force exerted on it:
Change in momentum = Final momentum - Initial momentum
= 0 kg·m/s - 15 kg·m/s
= -15 kg·m/s
Since the velocity of the water changes from 5 m/s to 0 m/s, the direction of momentum change is opposite to the initial momentum, resulting in a negative value.
Therefore, the force exerted by the water on the wall is equal to the change in momentum:
Force = Change in momentum
= -15 kg·m/s
The force exerted by the water on the wall is -15 kg·m/s or simply 15 N (since force is a vector quantity, direction matters for sign but not for the magnitude).
The force equals the rate of momentum change, which equals
(mass flow rate)x(velocity change)
The answer will be in Newtons.
You should have provided units (presumably m/s) with your velocity numbers.