A 5 kg block slides down a quarter circular surface as shown in the fig. It comes to rest at the lower end. What is the work done against friction ?

Q: A 5 kg block slides down a quarter circular surface as shown in the fig. It comes to rest at the lower end. What is the work done against friction ?

Numerical

(a) 100 J

(b) 75 J

(c) 50 J

(d) 150 J

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Ans: (c)

Sol: Loss in gravitational P.E = Work done against friction

m g h = Wf

5 × 10 × 1 = Wf

Wf = 50 J