Water leaves a hose at 2 m s⁻¹. The water in the hose has mass per unit length 100 kg m⁻¹. Find pumping power needed to supply the outgoing jet's KE.
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Water leaves a hose at 2 m s⁻¹. The water in the hose has mass per unit length 100 kg m⁻¹. Find pumping power needed to supply the outgoing jet's KE.

G1 Physics · Accepted Answer

Step 1 — Principle: Power equals the rate at which kinetic energy is imparted to the moving material. Step 2 — Working: Mass flow rate is (100 kg/m)(2 m/s)=200 kg/s. Step 3 — Working: KE per unit time =½ ṁv² =½×200×(2²)=400 W. Correct answer: A — 400 W.