Answer:
Yes, I'm pretty sure it is. That's why I don't click on it!
Answer:
Frictional force increases with the increase in the roughness of the surface.
Explanation:
You will see that the rougher the surface, the greater the wear and tear.
<span>The runner is moving by uniformly accelerated motion, starting from rest (so, his initial velocity is zero). The law of motion of the runner is
</span>

<span>
where x(t) is the distance covered after time t, and a is the acceleration of the runner. By re-arranging the formula, we get
</span>

<span>
We know the runner has covered a distance of S=12m in t=4.0 s, and if we plug these numbers into the equation, we find the acceleration of the runner:
</span>

<span>
</span>
The resistance of the silver block is given by

where

is the silver resistivity

is the length of the block

is the cross-sectional area of the block
If we plug the data into the equation, we find the resistance of the silver block: