Gravity
What force pulls objects toward Earth and gives us weight?
Gravity!
What is the name of the force that resists motion when two surfaces rub together?
Friction
What are the two ends of a magnet called?
Poles (North and South)
What word describes an object's tendency to keep doing what it's doing (stay at rest or keep moving)?
Inertia
If you drop a ball and a feather at the same time (ignoring air), what will happen because of gravity?
They will land at the same time.
Key: ignore air resistance
Which surface will usually cause more friction: rough sandpaper or smooth glass?
Sand Paper
Name two materials that are commonly attracted to magnets.
Iron and Steel
What type of force does not allow motion?
Unbalanced
Name two factors that affect how strongly gravity pulls on an object.
The mass of the objects and the distance between them.
Give one way friction can be helpful and one way friction can be a problem.
Helpful: allows us to walk without slipping; Problem: causes moving parts to wear or slows machines down.
If the north pole of one magnet is brought close to the north pole of another magnet, will they attract or repel?
They will repel against each other.
A book rests on a table. Name the two equal and opposite forces acting on the book vertically and explain why the book doesn't move.
Gravity pulling down and the normal force from the table pushing up; they balance so net force is zero.
A planet has much more mass than Earth. How would gravity on that planet compare to Earth's gravity for a person standing on it?
Gravity would be stronger; the person would weigh more.
How can you reduce friction between two surfaces? Give one real-life example.
Make surfaces smoother or add an "oil"; example: oiling a bicycle chain or using ball bearings.
Describe how you could test whether an unknown object is magnetic using simple classroom materials.
By bringing a magnet close to these objects and testing them one at a time.
Give an example of a push and an example of a pull from everyday life.
Closing a door and opening a door
Explain why astronauts feel "weightless" in orbit even though Earth's gravity is still acting on them.
They are in continuous free fall around Earth (orbiting), so both the spacecraft and astronauts fall together, creating the sensation of weightlessness.
Example: Roller Coaster in Weird but True video
A sled slides faster on packed snow than on deep, dry snow. Explain how friction and surface contact cause this difference
Packed snow provides a smoother surface and less resistance, so kinetic friction is lower; deep, dry snow increases surface irregularities and contact, causing greater friction and slower motion.
Explain why a compass needle points toward Earth's magnetic north. Include what part of Earth acts like a magnet.
Earth's core creates a magnetic field that behaves like a giant bar magnet; the compass needle (a small magnet) aligns with Earth's magnetic field and points toward the magnetic north pole.
Two children push a toy car the same distance. Child A pushes with a greater force than Child B. Explain, using ideas about net force and motion, how the car's motion will differ between the two pushes.
Child A applies a larger net force, so the car will accelerate more and likely reach a higher speed than with Child B's smaller force