Dont understand physics work question?

[elpermic]

Homework Statement

its for me midterm..

a person applies a constant force on an object of mass 20 kg that causes the object to move horizontally at a constant speed of 0.20 m/s through a distance of 0.80m . What is the work done on the object?

A) 0J
B) 10J
c)16J
d)160jNow the answer is 0J. But I don't understand why.. THe professor says its 0J and his reason is "Force counteracting gravity is perpendicular to the displacement."

Homework Equations

The Attempt at a Solution

is it because the question is saying what is the work done by the object?? because it doesn't say what's the work done on the object by the person..

 

[collinsmark]

Now the answer is 0J. But I don't understand why.. THe professor says its 0J and his reason is "Force counteracting gravity is perpendicular to the displacement."

Given what your professor said, I gather we are supposed to ignore friction. So, ignoring friction,...

The object is moving at a constant speed. What is the acceleration of an object moving at a constant speed?

Applying Newton's second law, what is the force on an object that is moving at a constant speed (and remember, for this problem we are assuming 0 friction)?

Thus the work done on that object is...?