STAAR SCIENCE 8TH REVIEW

• The cart was stationary with a velocity of 0 m/s for the entire 7 seconds. 
• The cart was stationary except for a short burst of acceleration of 0.5 m/s^2 . 
• The cart moved at a constant velocity of 0.5 m/s for the entire 7 seconds.
• The cart accelerated at a constant rate of approximately 0.8 m/s^2 . 

A pitcher throws a ball toward a player holding a softball bat. The player uses the bat to hit the ball. The bat applies a 10 newton force to the ball. Which statement correctly describes the reaction force between the bat and the ball?

• the reaction force is the force that causes the ball to move toward the bat

• the reaction force is the force applied to the bat by the player holding the bat

• the reaction force is the force that pulls the ball toward the ground

• the reaction force is the force of the ball on the bat

• the mother moves forward, and the daughter moves backward with a greater acceleration

• both move forward, but the mother moves with greater acceleration

• the mother moves backward, and the daughter moves forward with a greater acceleration

• both move backward, but the daughter moves with a greater acceleration

Researchers are studying lichens growing on trees in a forest ecosystem. At the beginning of the study, the researchers identified twelve lichen species in the forest. Later, a forest fire happened in the study area. The researchers returned to the area and found only six lichen species. Which inference is best supported from the researcher's observations?

• most lichen species are unaffected by forest fire

• the biodiversity in a forest increases after a fire

• certain lichen species are better adapted to survive forest fires than others

• forest fires will permanently remove certain species from the ecosystem

Which statement best describes evidence that a chemical reaction occurs as a cake bakes?

• the water in the cake batter evaporates

• the cake rises as gas bubbles form in the baking cake

• the cake takes the shape of the container in which it is baked

• the water in the cake batter is used to keep the cake moist as it bakes

• 4 carbon atoms, 11 hydrogen atoms, and 1 oxygen atom

• 7 carbon atoms, 14 hydrogen atoms, and 1 oxygen atom

• 7 carbon atoms, 11 hydrogen atoms, and 8 oxygen atoms

• 6 carbon atoms, 14 hydrogen atoms, and 3 oxygen atoms

• 40,000 N
• 100 N
• 100 m/s^2
• 10,000 kg

• the proposed law will protect the lake because plant roots between the wetland and the lake will stop pollution from entering th elake

• the proposed law ill not protect the lake because animals that live in or near the lake will add pollution to the lake

• the proposed law will not protect the lake because groundwater will carry pollution from the weland directly into the lake

• the proposed law will protect the lake because the high elevation of the water table will block pollution from entering the lake

In the equation,          2Mg + O₂ ---> 2MgO, which are the reactants?

• Mg and O
• MgO
• Mg and MgO
• O and MgO

• The book, the ball, and the car 
• The ball, the car, and the bird 
• The can, the swing, and the bird 
• The book, the ball, the can, and the swing