| Answer | Crossword Clue |
|---|---|
| friction | The action of one surface or object rubbing against another |
| frictional | Of or produced by the action of one surface or object rubbing against or moving over another |
| friction | The resistance that one surface or object encounters when moving over another |
| collision | An instance of one moving object or person striking violently against another |
| collisions | An instance of one moving object or person striking violently against another |
| impacts | The action of one object coming forcibly into contact with another |
| impact | The action of one object coming forcibly into contact with another |
