Balanced, Unbalanced, and Net Forces

A force can be best described as:

• a push or pull

• something that is exerted

• a change in velocity over change in time

• gravity or friction

Which of the following is an example of a net force?

• a 10 kg box of books has inertia

• a car travels at a constant velocity of 10 m/s

• a car in motion will tend to stay in motion, while a car at rest will tend to stay at rest

• friction pushes against an object, slowing it down

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NGSS.MS-PS2-2

A tree is standing still. The wind begins to blow and the tree bends. Which statement best explains how you could tell that a net force was acting on the tree?

• the tree was already in motion and changed direction

• the tree had momentum

• the tree was already in motion and sped up

• the tree was stationary and began to move

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NGSS.MS-PS2-2

In which situation does the motion of an animal show that a net force is acting on that animal?

• At 0 s, a snake slithers forward with a velocity of 2 m/s. 5 s later the snake's velocity is 2 m/s.

• An eagle remains flying at a constant velocity.

• A sparrow remains stationary perched on a power line.

• A running tiger increases its speed from 4 m/s to 6 m/s.

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NGSS.MS-PS2-2

Which of the following statement best states Newton's second law?

• The net force on an object will equal the mass of the object multiplied by its velocity.

• Any one force that acts on an object will equal the mass of the object multiplied by its acceleration.

• Any one force that acts on an object will equal the mass of the object multiplied by its velocity.

• The net force on an object will equal the mass of the object multiplied by its acceleration.

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NGSS.MS-PS2-2

Choose the best ending. If an object is traveling with a constant velocity...

• There are only forces parallel to the direction of motion.

• There is no net force on the object.

• There are no forces on the object.

• There are no forces parallel to the direction of motion.

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NGSS.HS-PS2-1

You see an object accelerate towards the left. Which of the following statements is correct?

• There is a net force on the object to the left.

• There is a net force on the object upwards.

• There is a net force on the object to the right.

• There is a net force on the object downwards.

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NGSS.MS-PS2-2

You observe two teams in a tug-of-war. The red team is moving towards the blue team with a constant velocity. Which of the following statements must be true?

• The red team is stronger (has a greater pulling force) than the blue team.

• The blue team is stronger (has a greater pulling force) than the red team.

• There are no forces acting on the red team.

• There is no net force on the red team.

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NGSS.HS-PS2-1

A vase of flowers is stationary on a table. Which of the following statements best explains why the vase is stationary?

• Gravity pulling down on the vase and the force of the table pushing up on the vase are equal.

• There are net forces on the vase.

• The force of gravity pulls the vase downwards.

• There are no forces on the vase.

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NGSS.MS-PS2-4

What is the net force on a car if the force of friction is 15 N and the forward force due to the engine is 20 N?

• 5 N forwards

• 5 N backwards

• 35 N forwards

• 35 N backwards

Tags

NGSS.MS-PS2-2