Question

holding a suitecase over a heAd for 5 minutes . has done some work

Answer 1

No,there is no work done.
It is because two conditions need to be satisfied for work to be done : (1) a force is acting on the body and
(2) body must be displaced
But in this case, holding a suitcase for 5 mins. won't have any acting force or may be gravitational force is there and the body or object is not been displaced. Hence we can say that work is not done.
Hope it will help.