Sagot :
Answer:
W = 6.5 W
Explanation:
Work is defined by
W = F . d
W = f d cos tea
where the point represents the scaled product and the bold letters indicate vectors
they ask us the work of the friction force
we write the translational equilibrium equation
y Axis
N -W = 0
N = mg
x axis
F - fr = 0
F = fr
the formula for the friction force is
fr = μ N
we substitute
fr = μ m g
we substitute in the equation of work
W = fr d cos θ
W = μ m g d cos θ
let's calculate
W = 0.500 1.10 9.8 Σ d_i cos θ_i
W = 5.39 d cos tea
we have two displacement
the first on one side of the box, suppose that side is on the y-axis, therefore the angle between the displacement and the friction force is 70º
and there is a second displacement in the x axis, in this case the angle between the friction force and the displacement is 30º
therefore the total workload is the sum of those work
W = 5.39 (1 cos 70 + 1 cos 30)
W = 5.39 (0.342 + 0.866)
W = 6.5 W