Equal and Unequal Forces

Equal forces are-

• forces that have the same strength.

• forces that have different strengths.

• one force that acts on both moving and nonmoving objects.

• a force between surfaces that slows objects or stops them from moving.

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NGSS.MS-PS2-1

Unequal forces are-

• forces that have the same strength.

• forces that have different strengths.

• one force that acts on both moving and nonmoving objects.

• a force between surfaces that slows objects or stops them from moving.

Friction is-

• forces that act together on an object without changing its motion

• forces that do not cancel each other out and cause an object to change its motion.

• one force that acts on both moving and nonmoving objects. A force that pulls objects.

• a force between surfaces that slows objects or stops them from moving.

Which picture is an example of equal forces?

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Tags

NGSS.MS-PS2-1

Which picture is an example of friction?

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NGSS.MS-PS2-2

In the illustration, a brick is tied to the end of a rope. Why is the brick not moving?

• The force of gravity is gone because the brick is held up by the rope.

• The force of gravity on the brick is equal to the upward pull of the rope.

• Both the force of gravity and the rope pull the brick upward.

• The force of gravity is too strong for the brick to move.

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NGSS.MS-PS2-2

NGSS.MS-PS2-4

Observe the chart. Aida was investigating how forces affect the flight of a paper airplane. The chart shows her paper airplane flight. Are the forces acting on the airplane in the chart equal or unequal?

• equal forces, because the height of the airplane is not changing

• equal forces, because the airplane does not have an engine

• unequal forces, because the airplane is in motion above the ground

• unequal forces, because gravity is pulling the airplane downward

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NGSS.MS-PS2-2

NGSS.MS-PS2-4

Observe the photo of the glider in flight. When the glider starts to fall, which statement best explains the forces acting on it?

• The upward force on the glider becomes weaker than the downward force of gravity.

• The downward force on the glider becomes stronger than the weight of the glider.

• The force of gravity changes direction to pull the glider downward.

• The glider begins moving so slowly that only gravity can affect it.

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NGSS.MS-PS2-2

A mouse, a dog, and a boy each try to roll the same heavy bowling ball. The table shows the results. When were unequal forces acting on the ball?

• when both the dog and boy rolled the ball

• only when the mouse tried to roll the ball

• only when the dog rolled the ball

• when all three bowlers rolled or tried to roll the ball

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

Observe the illustration. This illustration shows a toy car placed on a ramp. When the car is let go, it will begin to roll down the ramp. What can be concluded about the forces acting on the toy car as it is rolling?

• The force pulling the car down the ramp is equal to the force of friction with the ramp.

• The forces of gravity and friction both pull the car down the ramp.

• The force pulling the car down the ramp is greater than the force of friction on the ramp.

• The force of gravity is acting on the toy car, but the force of friction is not acting on it.

Tags

NGSS.MS-PS2-4