What does the conservation of mass in chemical reactions imply?

• Mass is created during chemical reactions.

• Mass is destroyed during chemical reactions.

• Mass is rearranged but conserved during chemical reactions.

• Mass is irrelevant in chemical reactions.

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NGSS.MS-PS1-5

How is average speed calculated?

• Speed = Time/Distance

• Speed = Distance/Time

• Speed = Distance × Time

• Speed = Distance + Time

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NGSS.MS-PS3-1

According to Newton's First Law of Motion, what happens to an object when balanced forces act on it?

• The object accelerates.

• The object changes direction.

• The object remains at rest or moves at a constant speed.

• The object stops moving.

What is the formula for calculating acceleration based on net force and mass?

• a = m/F

• a = F × m

• a = F/m

• a = F + m

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NGSS.MS-PS2-2

Explain why the total mass of reactants is equal to the total mass of products in a chemical reaction. Use the concept of atomic rearrangement in your answer.

• Atoms are destroyed in a chemical reaction.

• Atoms are rearranged but not created or destroyed.

• Atoms are created in a chemical reaction.

• Atoms are lost during a chemical reaction.

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NGSS.MS-PS1-1

NGSS.MS-PS1-5

A car travels 150 kilometers in 3 hours. Calculate its average speed.

• 50 km/h

• 45 km/h

• 60 km/h

• 55 km/h

A student records the distance traveled by a toy car every second for 10 seconds and plots a distance-time graph. Describe what it means if the graph is a straight line sloping upward.

• The toy car is moving at a constant speed.

• The toy car is accelerating.

• The toy car is decelerating.

• The toy car is stationary.

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NGSS.MS-PS3-1

A force of 20 newtons acts on a 4-kilogram object. Calculate the acceleration of the object.

• 5 m/s²

• 4 m/s²

• 6 m/s²

• 3 m/s²

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NGSS.MS-PS2-2

When you push against a wall, the wall pushes back with an equal force. Explain how this demonstrates Newton’s Third Law of Motion.

• Forces are unidirectional.

• Forces are equal and opposite.

• Forces are unequal and opposite.

• Forces are equal and in the same direction.

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NGSS.MS-PS2-1

A 20 kg bike accelerates at 10 m/s².  what was the force?

• 25 Newtons
• 20 Newtons
• 200 Newtons
• 10 Newtons

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NGSS.MS-PS2-2