8th Grade 1st Semester Review

Front

What is a chemical change?

Back

A chemical change is a process where substances combine or break apart to form new substances, often accompanied by energy changes. Examples include iron rusting and wood burning.

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. An example is water evaporating.

Front

What is velocity?

Back

Velocity is the speed of an object in a specific direction. It is a vector quantity.

Front

What is speed?

Back

Speed is the distance traveled per unit of time, regardless of direction. It is a scalar quantity.

Front

What does the Hertzsprung-Russell Diagram show?

Back

The Hertzsprung-Russell Diagram is a scatter plot of stars showing the relationship between their absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.

Front

What is acceleration?

Back

Acceleration is the rate of change of velocity of an object. It can be calculated as the change in velocity divided by the time over which the change occurs.

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What is the difference between distance and displacement?

Back

Distance is the total path length traveled by an object, while displacement is the shortest straight line from the initial to the final position, including direction.

Front

What is a vector quantity?

Back

A vector quantity is a physical quantity that has both magnitude and direction, such as velocity and acceleration.

Front

What is a scalar quantity?

Back

A scalar quantity is a physical quantity that has only magnitude and no direction, such as speed and mass.

Front

What is the formula for calculating speed?

Back

Speed = Distance / Time.