Friction
True or False: Friction opposes (stops) motion
True! Friction opposes (stops) motion.
When forces are acting on an object, and they cause the object to change its motion, then the forces are ___________.
Unbalanced
Name 3 objects that are magnetic.
Certain metal objects
If someone pushes an object, which direction will the object go? (away from the force or closer to the force)
Away
True or False: Friction occurs even when there is no motion.
True! Friction occurs even when there is no motion.
When forces are acting on an object and the object is at rest, then the forces are _____________.
Balanced
North poles ______ to south poles. (Attract or repel)
Attract
If someone pulls an object, which direction will the object go? (away from the force or closer to the force)
Closer
True or False: Friction does not produce heat.
False! Friction does produce heat!
If something goes from a resting position to moving to the right, it changes ________.
Direction or motion.
The same poles _______. (attract or repel)
Repel
If you know a pattern of movement, you can ______ how it will move next.
Predict
Decide if the use of friction is helpful or harmful in these scenarios:
A. Starting a fire by rubbing sticks together.
B. Walking on ice while in a hurry.
A. Helpful
B. Harmful
What 2 forces are acting on an object when someone knocks a cup off a table?
Push and Gravity
Which two forces do maglev trains use to levitate?
Push and Magnetism
Can we predict the motion of an object that moves in regular patterns?
Yes, we can!
Name 5 characteristics of the force of friction.
In any order:
1. It opposes motion or potential motion
2. It occurs when objects are in contact with each other.
3. Friction can produce heat.
4. Friction can be helpful or harmful.
5. Makes motion difficult
What is force?
Force is a push or a pull
True or False: Magnetic forces act on objects even when they are not touching.
True
What does lubricant do?
Reduces (lessens) friction