Question

a force f is applied on an object and its displaced by the distance d give expression for work done when angle between force and displacement are degree (i) 0 degree (ii) 180 degree specify whether the work done is positive or negative in each case

Answer 1

1. so in the first case the angle is 0

so workdone = force *displacement costheta okay

so in the first case cos theta = 0

cos theta is nothing but the angle between the force and displacement okay

and it has values like for angle 0 it has value of 1

and one means the workdone is positive. okay

2. now in the second case the cos theta = 180

and cos180 = -1

so in this case the work done is negative

is you have any doubt then please ask me