Question

Work done by friction :
(a) is always negative (b) may be positive
(c) is always zero (d) is always positive

Answer 1

Answer:

(a) is always negative

Explanation:

As friction itself meaning it opposes work. So it can never be zero or positive.

also friction zero is an ideal condition.

so answer should be a.

Answer 2

Answer:

a)is always negative

Explanation:

Friction opposes the motion of a body

so the work done through it is negative (-).