Answer:
The third option (foot/1 hour)
Step-by-step explanation:
The formula for an infinite geometric sequence is the following:

Just substitute the values of

and r into the formula.



Therefore, the answer is 20.
Answer:
Friction is a force that opposes motion between any surfaces that are touching. Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. ... Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy