1994 grandam 3.1L problem not starting

I have a 94 ganda am 3.1 L
I turned the key everthing comes on lights radio good power but the car won't turn over. The battery looks good posts are clean and tight. Tried to jump still nothing

It did it before i held the key in the on postition for 20 sec and if eventually started. I did again but this time it's not starting. :disappoin

What would the problem be ?

thanks

Classic starter issue.

I bet that if you hit the starter with an hammer that it will then start.

Classic starter issue.

I bet that if you hit the starter with an hammer that it will then start.

thanks thephantom
i tried that a it worked..... I guess the starter is going bad.

thanks