Question

when a force (8i+4j)N displaces a particle through (3i-3j)m. then the power is 0.6W . the time of action of force is

Answer 1

Hence the time. of action of force is 20 seconds

Answer 2

Given:

Force 'F' = (8i + 4j) N

Displacement 's' = (3i - 3j) m

Power 'P' = 0.6 W.

To Find:

The time of action of force 'T'.

Solution:

Work done = F.s

= (8i+4j).(3i-3j)

= 24 - 12 = 12 J.

[ i.i = 1, j.j = 1, i.j = 0, j.i = 0 ]

Power = Work done / Time taken

Therefore,

Time taken = Work done / Power

T = 12 / 0.6

T = 120 / 6

T = 20 s.

The time of action of force is 20 seconds.