Jo Noble Follin, 54, a former mathematician at the Applied Physics Laboratory of Johns Hopkins University, died Friday at Suburban Hospital in Bethesda following a stroke.

Mrs. Follin worked at the laboratory from 1950 to 1955, and helped pioneer the use of computers to simulate missile flights.

Her job was to compute mathematically the flight trajectory and even the aberrations of the proposed missile during those early days of rocket and jet propulsion research.

She was the wife of Dr. James W. Follin, who at the time of their marriage was supervisor of the research program and is now a senior scientist at the laboratory.

Mrs. Follin was born in Lawson, Ky., and earned a bachelor's degress in education and mathematics at Ohio State University.

Following graduation in 1946, she joined the Curtis Wright Aviation Co., now North American Aviation, as a mathematician at its plant in Columbus, Ohio. She conducted studies in stress analysis and in the efficiency and reliability of material and equipment. She worked for the aviation company until she moved here and began work at the Johns Hopkins lab in 1950.

In addition to her husband, she is survived by a son, James, both of the home in Rockville; her mother, Mrs. Shade Noble, of Lawson; two sisters, Alma Miller, of Detroit, and Genelle, of Dayton, Ohio; and four brothers, Roy Noble, of Jackson, Ky., Raymond Noble and Winford Noble, both of Detroit, and Joseph Noble.