Answer to Question #286181 in Classical Mechanics for cole

Question

Hard-working Manny is forced to pull a 1000 [N] box located at the bottom of the inclined plane using a string with a force of 2000 [N] until it reaches the top of the inclined plane. The frictionless inclined plane has a surface length of 3.0 [m] and makes a 30◦ angle with respect to the ground. What is the total work done on the box?

Answer 1

By the definition of the work done, we get:

$$W_{tot}=F_{tot}d=(F_{pull}-Wsin\theta)d,$$ $$W_{tot}=(2000\ N-1000\ N\times sin30^{\circ})\times3\ m=4500\ J.$$