Scope 9 & 10: Newton's Third law and Net Force

Match the following

• 1. Direction

• ____ The law that states that for every action
  force there is an equal and opposite reaction force.

• 1. Force

• ___ A push or pull that can change the motion
  of an object

• 1. Magnitude

• ____ The action and reaction forces that occur
  at the same time when a force is applied to an
  object and the object applies a force equal in
  magnitude but opposite in direction back on the
  original object

• Newton's third law of motion

• ____ A straight path that an object can move along

• 1. Force pairs

• ____ The size or quantity of something

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NGSS.MS-PS2-1

Label the following

a

b

Action Force

Reaction Force

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1. 
   If a glass of sweet tea exerts a force of 25 newtons on your kitchen table, what is the force and its direction that the table exerts on the glass of sweet tea?

• 0N

• Tables don't give force

• 25N

• 25

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NGSS.MS-PS2-5

According to Newton’s third law, if someone jumps off a skateboard, then the skateboard will roll backward because–

2. t

• 1. the mass of the skateboard is the same as the mass of the person who jumps off.

• 1. he pull of gravity on the person is the same as it is on the skateboard, regardless of size.

• 1. the air resistance on the person is great and the friction on the skateboard is small.

• 1. for the force that sends the person forward, there is an equal force pushing back on the skateboard.

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1. Newton’s third law of motion states that–

• 1. if two objects receive the same amount of force, then the object with the larger mass will travel slower than the object with the smaller mass.

• 1. for every action force, there is an equal and opposite reaction force.

• 1. a body at rest remains at rest unless it is acted on by a force.

• 1. a body in motion stays in motion unless it is acted on by a force.

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NGSS.MS-PS2-1

Jalen made a chart of observations to identify which objects have balanced forces acting on them and which have unbalanced forces acting on them. Using the data that Jalen collected, what is the best conclusion about the observations?

• 1. When the force on an object is equal, there is motion; when the force is unequal, the object is stationary.

• 1. When the force on an object is equal, there is no motion; when the force is unequal, motion occurs.

• 1. When the force on an object is both equal and unequal, motion does not occur because there is no friction

• 1. When the force on an object is both equal and unequal, motion occurs because of friction.

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NGSS.MS-PS2-2

The nozzle of a rocket is pointed downward so that as fuel is ignited, the exhaust pushes downward. Why is this arrangement necessary for a rocket to function properly?

• 1. The rocket is protected from the heat of the exhaust.

• 1. Burned fuel can be collected on the ground.

• 1. As fuel is combusted, the rocket pushes the gases backward and the gases push the rocket forward.

• 1. This allows the rocket to be steered properly.

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NGSS.MS-PS2-2

4. Every Saturday morning, Jada plays tennis with her stepsister. Jada’s racket experiences a force of 25 N as it hits the ball. What is true about the force that the ball will experience?

• 1. The ball will experience 25 N of force.

• 1. The ball will experience 50 N of force.

• 1. The ball will experience 10 N of force.

• 1. The ball will not experience any forces.

Tags

NGSS.MS-PS2-1

According to Newton’s third law, if someone jumps off a skateboard, the skateboard will roll backward because–

• • A

    the mass of the skateboard is the same as the mass of the person jumping off the skateboard.

• • B

    the pull of gravity on the person and the skateboard is the same despite size.

• • C

    the air resistance on the person is greater, and the friction on the skateboard
    is lesser.

• • D

    the force pushing the person forward is equal to the force pushing back on
    the skateboard.

Tags

NGSS.MS-PS2-1

Jayden is building a treehouse in his backyard. When he strikes the nail with a hammer, he uses a force of 50 newtons. Jayden notices every time he strikes the nail with the hammer, the hammer–

• • moves in the same direction as the nail with a force of 100 newtons.

• • B

    moves in the opposite direction of the nail with a force of 100 newtons.

• • C

    moves in the opposite direction of the nail with a force of 50 newtons.

• • D

    stays stationary with no force.

Tags

NGSS.MS-PS2-1