Question

What is angle between force and direction of displacement when
Work is equal to 1)Zero
2)Negative

Answer 1

Work is defined as product of force and component of displacement in the direction of force.
W= FS 
When force and displacement are in same direction.

When force Is applied with some angle with displacement vector then work:
W= FSCosϴ

POSITIVE WORKDONE:
---> WHEN FORCE AND DISPLACEMENT ARE IN SAME DIRECTION.
ϴ=0 , WORK DONE POSITIVE.

NEGATIVE WORK DONE:
As the force and displacement are in opposite directions.
ϴ= 180 , work done is negative.

Zero work done:
When force does not act on object work done is zero.
If force acts and still objects does not move them also work done is zero.
If ϴ=90 then also work done is zero.

Answer 2

Explanation:

---> WHEN FORCE AND DISPLACEMENT ARE IN SAME DIRECTION. ϴ=0 , WORK DONE POSITIVE. ... If force acts and still objects does not move them also work done is zero. If ϴ=90 then also work done is zero.