STAAR Category 2: Force, Motion, and Energy (2019)

A mother and daughter press their hands together and then push apart while ice skating.

Immediately after they push away from each other, how does the motion of the mother and daughter change?

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

• Both move forward, but the mother moves with a 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.

The net force on a vehicle that is accelerating at a rate of 1.5 m/s2 is 1,800 newtons. What is the mass of the vehicle to the nearest kilogram?

A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains motionless?

• There are no forces acting on the rock.

• The only force acting on the rock is directed toward the sidewalk.

• The forces acting on the rock are all balanced.

• The sidewalk exerts an unbalanced force on the rock.

The distance a toy car travels over time is shown in the graph.

Which table best shows the average speed of the toy car at different time intervals?

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The blades of a wind turbine are at rest until the movement of air causes the blades to spin.

Which energy transformation happens when the blades are spinning as shown?

• Electrical to mechanical

• Chemical to electrical

• Mechanical to electrical

• Chemical to mechanical

The graph shows the distance an object traveled in 11 seconds.

Which answer choice best describes the movement of the object between the times of 0 and 6 seconds on the graph?

• Moving at a constant speed

• Accelerating

• Moving toward the north

• Stopped

The diagrams show forces acting on a toy car as it moves to the right. Which diagram shows the toy car that will most likely accelerate to the right based on these conditions?

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Researchers are investigating processes that happen during digestion. Which answer choice describes only a physical change during digestion?

• Hydrochloric acid in the stomach breaks down proteins.

• Chewing in the mouth breaks food into small pieces

• Enzymes in saliva start the digestion of starches before food is swallowed.

• Bacteria in the intestines convert dietary fiber into fats.