I know from experience, these sections are not easy to understand until they are explained, so I will try.

We know that velocity is looking how(where) an object has moved over a period of time

v=(position)/(time)

for example if you start on your walk,

you take 10 steps in 5 seconds, then

v=10(steps)/5(sec)=2 steps per second

now consider you are going on a longer walk

for, lets say, 10 minutes

for two minutes you walk at the same rate of 2 (steps/sec) then you reach a hill and your pace slows for 2 min. of 1(step/sec), you reach the top and going down the other side you walk at 3 (steps/sec) for 1 min, then you reach a busy intersection and have to wait for 1 min. before you can continue (0 (steps/sec)) you cross and go back to your normal pace of 2 (steps/sec) then a dog chases you for the next 2 min so you run at 10 (steps/sec).

now set up your vel-vs-time graph

velocity on the y-axis and time on the x-axis.

if you graph these with sharp changes at (2,4,5,etc) each of those flat lines (horizontal) tells us the velocity was not changing, and the slope is 0 when the velocity does not change. Now I’m sure you read something about what changing velocity means.

a=(change in velocity)/(change in time)

1) if velocity is constant(NOT changing), acceleration is 0 (slope is 0) and the graph has a horizontal line.

2) if velocity is increasing, acceleration is positive (object is speeding up) and the slope is positive.

3) if velocity is decreasing, acceleration is negative or decelleration occurs (object is slowing down) and the slope is negative.

while you can draw your graph with horizontal lines connected with vertical tangents you can also imagine it took you a step or two in between each change of pace and connect those regions with smooth curves those smooth curves are your areas of acceleration.

once you have had calculus, kinematics will make much more sense

The slope of an object going at a constant speed, the line would be straight.

When the slope is changing, it means the velocity is changing. An example of this would be something that is thrown into the air and falls back to Earth. (it starts off at a certain speed, reaches the apex, stops, then falls back)

A slope is telling you that there is a change in motion, a positive would be speeding up and a negative would be slowing down.

What type of motion happens when the slope is constant?

A constant slope is where the motion is the same speed througout.

What type of motion happens when the slope is changing?

When the slope is changing, then the rate that the object is moving is changing in an inconsistant way.