In which of the following situations is the work done by the indicated force zero? The tension force acting on a pendulum as it swings. The Earth's gravitational force acting on the moon as it moves along its circular orbit. The normal force acting on a person as they walk across a room. The force exerted by a person's arm as they carry a suitcase across the lobby of a hotel.

Question

vincent-lyon.fr · Answer

Do you have an idea?

anonymous · Answer

I want to say the normal force acting on a person, but I'm not sure.

vincent-lyon.fr · Answer

You are right ! 
But it is not the only correct answer...

anonymous · Answer

My online homework will only accept one answer, but thanks!

vincent-lyon.fr · Answer

Then the question is incompatible with the way your online homework works!