Vocabulary
What is the term for a push or pull on an object?
Force
Which force causes a hockey puck to eventually stop sliding on ice?
Friction
Explain what happens to the net force on an object if two equal forces act in opposite directions.
They cancel out (net force = 0), and motion doesn’t change.
A physical change changes the _______ but not the _______ of a substance.
Appearance; composition
What type of element is Zinc (Zn)?
Metal
What is the amount of mass in a given volume?
Density
If a tree pushes back with 10 N after being pushed, which law explains this?
Newton’s Third Law (equal and opposite forces)
A soccer ball is kicked with a force of 12 N to the east. Friction acts with 4 N to the west. What’s the net force and motion direction?
8 N east; moves east
Which of the following is a chemical change: melting ice, rusting metal, or dissolving sugar?
Rusting metal
Which property best describes a metal?
Conductive, malleable, high melting point
What do we call the force that resists motion between two surfaces?
Friction
When a seat belt stops a person from flying forward in a crash, what direction is the force applied?
Opposite direction of motion
A magnet attracts iron filings but not sand. Explain why this separation works.
Iron is magnetic; sand is not, so only iron moves toward the magnet.
What evidence shows a chemical change has occurred?
Gas bubbles, temperature change, or color change
Which elements are used as semiconductors in electronics?
Metalloids
What is the force that pulls objects toward Earth?
Gravity
A gardener lifts a wheelbarrow upward with a force of 76 N. What is the net force acting on it?
76 N up
A ball with a density of 1.73 g/cm³ will rest between which liquids?
Between the two liquids whose densities are just above and below 1.73
When two substances combine to form a new one, what type of change is it?
Chemical change
What is a metalloid?
An element with properties of both metals and nonmetals
What is the difference between balanced and unbalanced forces?
Balanced = no change in motion; Unbalanced = causes motion
Two students push a box from opposite sides — one pushes with 12 N and the other with 7 N. What is the net force and direction?
5 N toward the stronger push
A student claims all objects with more mass sink. Explain why this is not always true using the concept of density.
Floating depends on density, not mass — an object with low density can float even if it’s heavy.
Explain how you can tell the difference between a physical and chemical change using examples.
Physical = no new substance (melting); Chemical = new substance forms (burning)
Explain how you can identify a metal just by observing its properties.
It’s shiny, conducts electricity, and can be shaped easily