Q. 84.7( 3 Votes )

In which of the following cases is the work done positive or zero or negative?

a) Work done by the porter on a suitcase in lifting it from the platform on to his head.

b) Work done by the force of gravity on suitcase as the suitcase falls from porter’s head.

c) Work done by the porter standing on platform with suitcase on his head.

d) Work done by force of gravity on a ball thrown up vertically up into the sky.

e) Work done by force applied by hands of a man swimming in a pond.

Answer :

a) Positive as the porter apply force on the suitcase in its direction of motion.


b) Positive as the gravity acts downward and suitcase is also falling downward


c) Zero Work is done as force exerted by its head on suitcase cause no motion.


d) Negative as the gravity acts downward and ball is moving upward.


e) Negative as the swimmer propels his hands back so as to get a forward displacement.


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Conservation of Mass-Energy41 mins
Cell Organelles of Energy Metabolism49 mins
Champ Quiz | 2-Dimension( Coordinate geometry )36 mins
Matter and Its Classification34 mins
Speed and Velocity59 mins
Wren and Martin | Grammar44 mins
India – size and location34 mins
Rest and Motion59 mins
Cell Appendages and Transport60 mins
Quiz | Thrust and Pressure54 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses
RELATED QUESTIONS :

Define work and write its units.

AP - Physics & Chemistry