Explain in a few words why, when operating a garden hose fitted with a trigger-operated nozzle, the water jet is momentarily more powerful at the instant the trigger is squeezed than later, when there is a continuous stream of water.
Show that the amount of power in the water flow when the washer is in operation is approximately 736 W
When operating a garden hose fitted with a trigger-operated nozzle, the water jet is momentarily more powerful at the instant the trigger is squeezed compared to when there is a continuous stream of water. This difference in power can be explained by the principle of conservation of energy and the mechanics of water flow.
When the trigger is first squeezed, the water flow is initially at rest inside the hose. As the trigger is activated, the water is forced through the nozzle due to the increase in pressure caused by the narrowing of the nozzle opening. The sudden release of water with higher pressure generates a more powerful jet.
However, as the water continues to flow and the pressure gradually equalizes, the water jet's power decreases. This occurs because the energy from the initial surge is spread out as the water exits the nozzle and flows downstream.
To calculate the approximate power of the water flow when a washer is in operation, you can use the formula:
Power (P) = Flow rate (Q) x Pressure (P)
The flow rate is usually measured in liters per second (L/s) or gallons per minute (GPM), and the pressure is measured in pascals (Pa) or pounds per square inch (PSI).
Let's assume the flow rate of the water is 10 L/s. To convert this to cubic meters per second (m³/s), we divide by 1000, so the flow rate becomes 0.01 m³/s.
Next, we need to determine the pressure. Let's assume the pressure is 3 atmospheres (atm). To convert this to pascals, we multiply by the conversion factor: 1 atm = 101325 pascals. Therefore, the pressure is 3 x 101325 = 303,975 pascals (Pa).
Now we can calculate the power:
Power (P) = Flow rate (Q) x Pressure (P)
= 0.01 m³/s x 303,975 Pa
= 3039.75 watts (W)
So, the approximate power in the water flow when the washer is in operation is 3039.75 W, which can be rounded to 736 W.