Chemical Changes
The ultimate proof that a chemical change has occurred rather than a physical change is the formation of a ______
New Substance
When two opposing horizontal forces acting on an object are equal in magnitude, the calculated net force is ______ N, meaning the forces are balanced.
Zero
According to Newton’s Third Law of Motion, whenever one object exerts a force on a second object, the second object simultaneously exerts a force back that is equal in ______ and opposite in direction
Magnitude (or strength)
The attractive non-contact force that pulls all objects with mass toward Earth’s center, such as pulling a thrown basketball back down to the court, is called -
Gravity
Matter that has a fixed, uniform composition throughout—consisting of only one single type of element or compound—is classified as a-
Pure Substance
When baking soda is added to vinegar, rapid fizzing and bubbling immediately occur, providing clear evidence of ________________.
Production of a gas
If two students push a stalled car to the right—one applying 15 N and the other applying 25 N—the net force acting on the car is ______ N to the ______.
40N to the right
When a swimmer’s hands push water backward to move through a pool, the water simultaneously pushes the swimmer’s hands ______ with an equal amount of force
Forward
A heavy science textbook rests motionless flat on a classroom lab table. Identify the two vertical forces (and direction of the forces) acting on the book that help to keep it stationary.
Normal Force (up) & Gravity (down)
A trail mix containing raisins, nuts, and chocolate chips is an example of a ______ mixture because its different ingredients remain visibly distinct and unevenly mixed.
Heterogeneous
When two clear liquid solutions are mixed together in a beaker and an insoluble solid powder forms and settles to the bottom, this solid is called a:_____________
Precipitate
A wooden sled experiences an applied force of 50 N to the right and a friction force of 20 N to the left. The net horizontal force acting on the sled is ______ N to the right, making the forces (balanced/unbalanced).
30N to the right / Unbalanced
In any action-reaction interaction, the two forces in a force pair occur ______, meaning both forces happen at the exact same instant in time.
Simultaneously
When a bicyclist squeezes the brake levers, rubber pads press against the spinning metal rims. The contact force acting opposite to the wheel's motion to slow it down is-
Friction
When sugar completely dissolves in a glass of warm water, it creates a __________ mixture also known as a solution, where the particles are spread evenly throughout.
Homogenous
Mixing two room-temperature liquid chemicals in a flask causes the outside of the container to feel noticeably cold to the touch, indicating a change in ______ energy during the reaction.
Thermal
A model rocket generates an upward engine thrust of 400 N while gravity pulls downward with 150 N. The net vertical force is (1)______ N upward, which will cause the rocket's speed to (2) (accelerate/decelerate) (3) (upwards/downwards).
250N / Accelerate upwards
A soccer player kicks a ball upwards with his foot. According to Newton's 3rd law, what is the reaction force?
The force the ball exerts back onto the player's foot
Gravitational force is an attractive non-contact force that acts between all objects with mass. What two factors affect the strength of the gravitational attraction between objects?
Mass & Distance between objects
What are the two main types of pure substances?
Elements and Compounds
An experimenter adds two drops of red dye to two separate beakers, each containing a different clear liquid. Beaker 1 turns light pink, while Beaker 2 turns blue. Which beaker shows evidence of a chemical change?
Beaker 2
A crate resting on a floor is pushed right with 12 N while friction pushes left with 12 N. Vertically, gravity pulls down with 10 N and the normal force pushes up with 10 N. The total net force in all dimensions is ______ N, so the crate's motion will ________.
0N / Stay still (motionless)
Marcus stands on a stationary skateboard on a smooth driveway. He jumps forward off the skateboard onto the grass. Identify the simultaneous force pair (action/reaction) that causes both Marcus and the skateboard to move.
Action: Marcus's feet push backwards
Reaction: Skateboard pushes forwards on Marcus's feet
What are the 5 main types of forces? Classify them as Contact or Non-Contact
Contact: Applied, Normal, Friction
Non-Contact: Gravity, Magnetism
A student tests a clear, uniform liquid in a lab. Unlike a pure compound, when this liquid is heated to boiling, it leaves behind a white crystalline solid at the bottom of the beaker, proving that the original liquid was a __________ ___________.
Homogenous Mixture