Physics??

[ajc]

Ok guys, who on my friends list is good at physics. I'm a complete moron and have never been able to figure out static friction problems. It's not explained well in the book. And I suppose they're easy enough, but for some reason I always mess them up. I just took a test and can't figure out if I answered the question right .....

A 24 kg object has horizontal forces -35N and F acting on it. The kinetic friction coefficient is 0.40. What force is needed to accelerate the object 3.5m/s?

Any takers??