The vector nature of forces hw ?

[eaglenerd]

I have been having trouble with this problem and don't understand why.

A shopper pushes a 7.5 kg shopping cart up at a 13 degree incline, find the magnitude of the horizontal force, needed to give the cart an acceleration of 1.41m/s2

The answer is supposed to be 28 N and I don't know how to get their

 

[Hootenanny]

Welcome to Physics Forums.

What have you tried thus far?