Answer:
A coefficient friction is a value that shows the relationship between two objects and the normal reaction between the objects that are involved.
Explanation:
The speed of the snail is given by:
![v=\frac{S}{t}](https://tex.z-dn.net/?f=%20v%3D%5Cfrac%7BS%7D%7Bt%7D%20%20)
where S is the distance covered by the snail and t the time taken.
The snail in the problem moves by S=18 mm in t=24 s, therefore its speed is
![v=\frac{S}{t}=\frac{18 mm}{24 s}=0.75 mm/s](https://tex.z-dn.net/?f=%20v%3D%5Cfrac%7BS%7D%7Bt%7D%3D%5Cfrac%7B18%20mm%7D%7B24%20s%7D%3D0.75%20mm%2Fs%20%20%20)
"did you press the switch?"
No, a body can not have its velocity constant, while its speed varies. Rather, it can have its speed constant and its velocity varying. For example in a uniform circular motion.