An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate of at which kinetic energy is imparted to water?

Options

(a) mv²
(b) 1/2 mv²
(c) 1/2 m²v²
(d) 1/2 mv³

Correct Answer:

1/2 mv³

Explanation:

m : mass per unit length
rate of mass leaving the the hose per sec
= mx / t = mv.
Rate of K.E. = 1/2 (mv)v² = 1/2 mv³