Idea 1of 8Builds onHow fast the speed changes
A push or a pull
What acts on a book that just sits there?
Today you'll discover
- what is pulling on a book that sits still
- why the table is doing something too
- the word for any push or pull
Think firstA book sits on a table. Anything acting on it?
The book is not moving. What is acting on it?
Decide first, then press Next. Watch where each arrow starts and points.
A square box with a dot at its centre resting on a heavy line. After a prediction, an arrow appears pointing straight down from the centre, then a second arrow of the same length pointing straight up. The last step swaps the table for a cord above the box and asks which forces act on a hanging lamp.
See the whole ideathe big idea and the key word, in one place
The big idea
A force is a push or a pull between two things.
Easy to get wrongA table is not doing nothing. Anything an object presses on presses back. Lift the table away and the book falls.
Key word
- force
- a push or a pull between two things; it has a size and a direction, so it is a vector
About this modelArrows are forces, not motion: a box can move with no arrow pointing its way.
Arrows are forces, not motion: a box can move with no arrow pointing its way.
Ready to use it?
- List every push and pull on an object that sits still.