Master carpenters say a sheet of plywood has to be well supported when it's being cut. If it isn't, it will sag and bind the saw blade, which can cause the saw to dangerously kick back at you.
The distance between the two sawhorses should be no more than five feet. To prevent sagging, place a two-by-four under each side of the plywood and one piece directly under the cut line.
If the saw is set properly, the blade will go just a hair deeper than the plywood's thickness and leave a small cut in the center stud under it.
The cut in the two-by-four is very shallow, you could still use it for another purpose.
Rick Good spent ten years in the newspaper business, including with The News & Observer (Raleigh, NC) and The Greenville News (Greenville, SC). He co-wrote, with Melinda Coleman, Rutledge to Riley: Governors of South Carolina, 1776–Present (Published by The Greenville News), and is the author of Mind Games Trivia #1 (Amazon). He has recently spent 15 years creating original trivia content through Sounds Good Mobile Entertainment and continues that with his new company, SGME Software. He edits The Smart Reader’s money, real estate, and business coverage.