Imagine a car, and imagine you see little arrows below and beneath it, just around it. <span>The path of a particle that is flowing steadily and without turbulence in a fluid past an object.</span>
free lil peezy and drake is kool
Good morning.
We have that:

, since we have rest in the inicial time.
The acceleration can be found with Newton's Law:

Now we put the acceleratin in the velocity equation:

We want the force, so, let's isolate
F:
That is because there are other forces like the friction forces that apply differently on both of them. The frictional forces applied to the sled are smaller than they are on the father, for example, so it's possible for him to pull it.
Speed is defined as the distance over time. So in measuring the speed of a car, the most manual thing that we can do besides using a speedometer is to measure a certain distance then measure the time at which the car passes that distance then divide the distance over the time. Then determine the speed limit.