Physics pt3

and write as many as you can. Check and repeat.

	P8 questions	Answers
	• What is a scalar quantity?	only has a size (magnitude)
	What is a vector quantity?	has both a size and direction
	3 What is a force?	a push or pull that acts on an object due to the interaction with another object
	• Is force a vector or scalar quantity?	vector
	5 What is a contact force?	when objects are physically touching (e.g., friction, air-resistance, tension, normal contact force)
	6 What is a non-contact force?	when objects are physically separated (e.g., gravitational, electrostatic, magnetic)
	Wraesthe awe biet the interaction ashrother?	the forces are the same size
	• When two oets interact witereach other of forces	* forces are in opposite directions
	© Whe isthes on tre resultant force on an object	:" zero
	10 What is the centre of mass?	the point through which the weight of an object can be E considered to act
	11 What is the turning effect of a force called?	a moment
	What can you say about clockwise and anticlockwise moments on a balanced object?	sum of all the clockwise moments about any point = sum of all the anticlockwise moments about that point
	1 How does a lever reduce the amount of force needed to create a particular sized moment?	by increasing the distance from the pivot
	1 What happens to the moment of a force when a small g gear drives a large gear?	moment is increased
	15 What does Newton's First Law say?	the valocity of an object will only change if a resultant E force is acting on it
	16 What is the resultant force on a stationary object?	행 zero
	Meady speedin straight linen object moving at a
	18 What does Newton's Third Law say?	g when two objects interact they exert equal and opposite forces on each other