Final answer:
The point on the edge of the tire moves through approximately 720 degrees in 1/7 of a second.
Step-by-step explanation:
To find the angle moved by a point on the edge of the tire, we need to calculate the angular displacement. The angular displacement is given by the formula:
Angular displacement = (number of revolutions) x (360 degrees)
First, we need to find the number of revolutions in 1/7 second. Since the tire rotates 840 times per minute, it rotates 840/60 = 14 times per second. Therefore, in 1/7 second, the tire rotates (14/7) = 2 times.
Now, we can calculate the angular displacement:
Angular displacement = 2 x 360 = 720 degrees