
Vectors Application 14
A 35kg trunk is dragged 10 m up a ramp inclined at an angle of 12 degrees to the horizontal by a force of 90 N applied at an angle of 20 degrees to the ramp. At the top of the ramp, the trunk is dragged horizontally another 15 m by the same force. Find the total work done.
My work:
W=90(15)cos32
=1144.86
W=343(10)cos78
=713
713+1144.86
=1857.9971
The answer in the book is 2114 J. How do I get this?

the question is very poorly worded ... apparently, the author meant for the applied force to be 20 degrees relative to both the incline and the horizontal surface ...
$\displaystyle 90\cos(20) \cdot 10 + 90\cos(20) \cdot 15 = 90\cos(20) \cdot 25 = 2114$ J