You may want to review Velocity before beginning this packet.
In this slide show I introduce the student to acceleration and how it is related to velocity and time.
The explanation is great but I want to ask the why acceleration is related to velocity and not speed
Great explanation Ariane. Another thing to keep in mind, Jack, is that speed does not care about direction, we say that it is a scalar quantity. However, velocity and a change in velogity (acceleration) do care about direction, we say that they are vector quantities.
Acceleration of an object is evidence that a non-zero net force is acting on the object. For example, if a car accelerates from rest to 20 m/s in 10 s, that is evidence that there was a net thrust on the car that pushed it forward. In this this case it would be +20m/s in 10 s, that is 2 m/s/s or 2 m/s^2.
But if an object moves at approximately constant speed in a circular motion (like for example the Moon in its orbit around the Earth), then there also is a net force acting on the Moon. This force is changing the direction of the motion of the Moon, which keeps it in orbit. Without this change in direction of the velocity over time (=acceleration), the Moon would continue flying through space at constant speed IN A STRAIGHT LINE. But since velocity is changing due to the change in direction (even though speed stays the same), we can say that velocity is NOT constant, and thus that there is acceleration.
So ACCELERATION is related to VELOCITY, not to speed.
If you scroll down towards the bottom of the page you will see a - and + magnifying glass on the bottom left of the slides. If you click the + button it should magnify the slides for you. You can also download the slides with the third button from the left (again at the bottom of the slides) and view them with a program capable of opening Powerpoint files. Hope that helps.