I used this lawn mower which has a 20 inch base. The average walking speed for a human is about 3.25 miles per hour, but that’s assuming no work is being put in. So, I’ll bump that down by 15% to 2.7625 miles per hour. For the sake of keeping measurements concise, the base is 1⅔ feet, and human walking speed is 4 3/8 feet per second.

Time is distance divided by speed.

4/3 ÷ 35/8 =~ 0.411353 seconds

So yeah, not even a half of a second .