When a car moves at a steady speed, the forces on it are balanced. The force from the engine is equal to that from friction such as air resistance. If a car moving at a steady speed then speeds up, the forces are no longer equal. They are unbalanced.
Your teacher is going to use a trolley to show the effects of balanced and unbalanced forces.
Complete the table. Add force arrows to the diagrams.
Description / Diagram of forces / Balanced or unbalanced forces?Trolley standing still /
Trolley moving at steady speed /
Trolley speeding up /
Trolley slowing down /
These diagrams show a sky diver falling from an aeroplane. Describe what is happening in each diagram, and say whether it is an example of balanced or unbalanced forces.
© Harcourt Education Ltd 2004 Catalyst 3
This worksheet may have been altered from the original on the CD-ROM.