Answer:
a) 633.39 J
b) 0.28
Explanation:
a)The kinetic energy of the player = [tex]\frac{1}{2} mv^{2}[/tex]
Work done by friction = energy change of the player
= [tex]\frac{1}{2} 67(4.35)^{2}[/tex] = 633.9 J
b) Assuming the frictional force stays constant,
Work done by friction = Frictional force×distance
Frictional force = kinetic friction(μ)×normal reaction
Normal reaction = weight = mass×gravitational acceleration ( g=10m/s2 )
Combining these equations
633.9 = F×3.4 ⇒ F = 186.44 N
F = μmg ⇒ μ = F/mg
= 186.44/670
= 0.28