The video is being made. Until it arrives, here is what it will say (120 words, about 60 seconds):

Here's a boy on a skateboard, rolling along a flat path at the same speed.

He pushes off with his foot, and he goes faster.

Then he drags his foot on the ground, and he goes slower.

Then his friend bumps him from the side, and off he goes a new way!

Faster, slower, a new way. What decided which one happened?

Now let's look at the forces. Each time, something pushed him.

Was it how strong the push was, or which way it acted?

That's this topic: what happens to a moving thing when the forces on it are not balanced.

Okay, so are you ready to find out what makes a moving thing go faster, slower, or turn?

It ends with a ready line. Then pick a reply below — any reply counts.