Okay, hun. Velocity is a vector quantity that measures displacement over a period of time. Velocity = Speed/Time (v=s/t). Hope this helped you. I took physics over 4 years ago. I'm more of a biology/chemistry person. (I major in those)
The work done to pull the sled up to the hill is given by

where
F is the intensity of the force
d is the distance where the force is applied.
In our problem, the work done is

and the distance through which the force is applied is

, so we can calculate the average force by re-arranging the previous equation and by using these data:
Newton's first law of motion states that. an object on the rest or motion is stay the same unless external force applied on it.
Answer:
Standard deviation = 3
Explanation:
Given


Required
Determine the standard deviation
First, we need to determine the variance;

This gives:



Know that:

Where SD represents standard deviation
This gives

Take square root


This is called average speed.Its really simple