Question

Find the work done by a force F of 15 pounds acting in the direction <2,-2> in moving an object 5 feet from (0,0) to (5,0).

Answer 1

Work is force times the distance. You are given the distance the object moved in the x axis direction. We also have to assume that there is no friction opposing the movement of the object since we don't see a coefficient of friction term.

So you need to find the force in the x axis direction to calculate the work being done.

We are given that the force is 15 pounds in the (2,-2) direction. So the force makes an angle of -45 degrees from the origin.

So to find the force in the x direction, multiply 15 pounds times cosine of-45 degrees.

15(cos(-45)) = 10.61 pounds

So the work done is 10.61 pounds times 5 feet or about 53 ft*lbs