Question

A) A 5.00-kg squid initially at rest ejects 0.250 kg of fluid with a velocity of 10.0 m/s. What is the recoil velocity of the squid if the ejection is done in 0.100 s and there is a 5.00-N frictional force opposing the squid’s movement?
(b) How much energy is lost to work done against friction?

Answer 1

Answer:

(a) The recoil velocity of the squid is 0.5 m/s

(b) W = 0.25 J

Explanation:

(a)

Momentum of the squid = momentum of the fluid

MV = mv

Where M = mass of the squid, V = recoil velocity of the squid, m = mass of the  fluid, v = recoil velocity of the fluid.

Making V the subject of formula,

V = mv/M

Where m = 0.25 kg, M = 5.00 kg, v = 10 m/s

V = (0.25 × 10)/5

V = 0.5 m/s

The recoil velocity of the squid is 0.5 m/s

(b)

Work done against friction (W) = Frictional force(F) × Distance(d)

W = F ×d.................... Equation 2

Where F = 5.0N, d = distance.

d = velocity × time

Where Velocity = 0.5 m/s, Time = 0.1 s

∴ d = 0.5 × 0.1 = 0.05 m

Substituting these values into equation 2,

W = 5 × 0.05

W = 0.25 J

Therefore 0.25 J of energy is lost to the work done against friction.