Question

A 67.6-kg boy is surfing and catches a wave which gives him an initial speed of 1.56 m/s. He then drops through a height of 1.65 m, and ends with a speed of 8.30 m/s. How much nonconservative work was done on the boy?

Answer 1

The nonconservative work was done on the boy is 1154.87 J.

Step-by-step explanation:

Given;

mass of the boy, m = 67.6 kg

initial speed of the boy, u = 1.56 m/s

height of fall, h = 1.65 m

final speed of the boy, v = 8.30 m/s

The initial energy of the boy is given by;

E₁ = K.E₁ + P.E₁

E₁ = ¹/₂mu² + mgh

E₁ = ¹/₂(67.6)(1.56)² + (67.6 x 9.8 x 1.65)

E₁ = 82.134 + 1091.475

E₁ = 1,173.61 J

The final energy of the boy is given by;

E₂ = K.E₂

E₂ = ¹/₂mv²

E₂ = ¹/₂(67.6)(8.3)²

E₂ = 2,328.482 J

The nonconservative work was done on the boy is given by;

W = E₂- E₁

W = 2,328.482 J - 1,173.61 J

W = 1154.87 J

Therefore, the nonconservative work was done on the boy is 1154.87 J.