HMH Module K Unit 1 Lesson 1 - Introduction to Forces

What is gravity?

• a contact force

• a frictional force

• a magnetic force

• a noncontact force

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NGSS.MS-PS2-4

Which of these is considered a contact force?

• the force between two magnets

• the gravitational pull of a planet

• the friction between an object and air

• the forces between two charged particles

A box has two forces acting on it. One force is 100 N upward. Another force is 50 N downward. What is the net force on the box?

• 50 N upward

• 100 N upward

• 50 N downward

• 100 N downward

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NGSS.MS-PS2-2

Melanie watched the path a baseball followed after a pitcher threw it. She noticed that the ball traveled horizontally away from the pitcher as well as downward toward the ground. What force caused the ball to accelerate in the downward direction when it was thrown? 

• applied force

• air resistance

• electrical force

• gravitational force

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NGSS.MS-PS2-4

Why are some forces considered to be noncontact forces? 

• Objects must be far apart in order to exert force. 

• Objects do not have to touch each other to experience force. 

• Objects push each other apart to increase the distance between them.

• Objects must be large in size in order to exert force that is strong enough to notice. 

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Why is the friction force considered to be a contact force? 

• Friction affects only solid objects. 

• Frictions always acts in the same direction. 

• Friction is produced when objects slide past each other. 

• Friction acts in a direction opposite to the direction of an object's motion. 

Why is magnetic force considered to be a noncontact force?

• Magnets must be far apart in order to exert a force. 

• Magnets do not have to touch each other to experience force. 

• Magnets push each other apart to increase the distance between them. 

• Magnets must be large in size in order to exert force that is strong enough to notice. 

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NGSS.MS-PS2-5

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A bird flies at 12.5 meters per second. The wind is blowing in the same direction at 4.5 meters per second. What is the bird’s speed when it flies with the wind?

• 7.0 m/s

• 8.0 m/s

• 12.5 m/s

• 17.0 m/s

A bird flies at 12.5 meters per second. The wind speed is 4.5 meters per second blowing in the opposite direction. What is the bird’s speed when it flies against the wind?

• 4.5 m/s

• 8.0 m/s

• 12.5 m/s

• 17.0 m/s

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NGSS.MS-PS2-2

Marek is pushing a heavy box across the floor. The arrow on the box shows the direction of the force he applies. What forces are acting on the box?

• Only Marek’s pushing force

• Marek’s pushing force and gravity only

• Marek’s pushing force, gravity, normal force from the floor, and friction

• Marek’s pushing force, gravity, and air resistance only

Tags

NGSS.MS-PS2-2