aim: what is friction? describe different types of friction. define the parts of a spring scale
TRANSCRIPT
Spring scale, pointer, spring, hook, friction, sliding friction, air resistance, rolling friction
AIM: What is friction?
What is the basic unit of measure of length in the metric system for length?
Meter
What is the basic unit of measure for mass in the metric system?
Gram
What is the basic unit of measure for volume?Liter
What is the basis unit of measure for force?
the NEWTON … N
On earth it take a force of approximately 10 N to lift a 1 Kg object
What is Friction?
Definition: Friction is the force which opposes the motion of an object.
EVERYBODY: Push your notebook across the table.
Why does it stop?
DEMONSTRATE: Rolling Friction
Slide a rolling chair across the room.
Does is stop?
Eventually
But does it move farther with the wheels then without?
Absolutely
DEMONSTRATE: Air Resistance
•Drop a flat piece of paper•Drop a crushed piece of paper•Can YOU explain why the flat piece took longer to reach to ground.
Is friction bad?
•Without friction, it’d be like walking on ice•Imagine peddling your bicycle on ice.
•Or wearing smooth soled shoes while playing basketball?
Is this a spring scale?
YES. Most scales are spring scales!
DON’T confuse a scale with a triple beam
balance. They are two different
things.
** Activity:
Using a Spring Scale.
1.Mass a book and several other small objects.2.What is the weight of the book?3.What are you measuring when you when you weigh an object? (gravity)
How much force (measured in N’s) does it take to lift a 1 Kg object?
10 Newtons
Define the parts of a spring scale.
Hook, pointer, spring
Describe three different types of friction: Sliding, rolling, air resistance