Excel Data Comparison – Lookup

I have two separate worksheets. Worksheet 1 contains a list of position #s (personnel). Worksheet 2 contains a list of position #s (Column A) with individual names (Column B). My task is to compare position #s in the two worksheets and when they match, copy and paste the corresponding user name from Worksheet B to Worksheet A adjacent to the appropriate position #. Any help would be appreciated.