Answer:
626.612 J
Explanation:
Work done by friction on the chair is given as
W-ΔEk = W'..................... Equation 1
Where W' = Work done by friction on the chair, W = Work done on the chair by me, Ek = change in Kinetic energy of the chair as a result of the slide.
From the question,
W = FdcosФ.............. Equation 2
ΔEk = 1/2m(v²-u²)................ Equation 3
Where F = Force applied on the chair, d = distance of slide, Ф = angle between the force and the horizontal, m = mass of the chair, v = final velocity of the chair, u = initial velocity of the chair
Substitute equation 2 and equation 3 into equation 1
W' = FdcosФ-1/2m(v²-u²)........................ Equation 4
Given: F = 156, d = 5 m, Ф = 26°, m = 18.8 kg, v = 3.1 m/s, u = 1.3 m/s
Substitute into equation 4
W' = 156×5×cos26°-1/2×18(3.1²-1.3²)
W' = 701.06-74.448
W' = 626.612 J.
Hence the work done by friction = 626.612 J
