Calculating Work on Incline: Solving for Gravitational Force Work

[mrnastytime]

Homework Statement

A horizontal force of magnitude F = 197 N is used to push a box of mass m = 5 kg from rest a distance d = 13 m up a frictionless incline with a slope q = 34°.

Homework Equations

How much work is done on the box by the gravitational force during this same displacement?

The Attempt at a Solution

Wg=mgh
Wg=5*9.81*7.3
i got 7.3 by using sin34=h/13
Wg=358.1 J
The answer i got is wrong according to the online hw. What am i missing? did i use the wrong formula?

 

[LowlyPion]

Maybe it would be negative?

Work by you is +, work by gravity is stored as potential = (-)?

 

[mrnastytime]

wow, it is negative. thank you very much!