Newton's Laws, Speed, Work, Power, Force Review

Which of the following is true about non-contact forces?

• Electrically charged objects need to be touching in order to attract or repel one another.

• Objects that are oppositely charged are attracted to one another and will move closer together.

• Every object exerts a pull on every other object because of friction.

• Every object exerts a pull on every other object because of magnetism.

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NGSS.MS-PS2-3

NGSS.MS-PS2-5

Forces push on an object at different times and cause its motion to change. When is there no acceleration of the object?

• When it first starts moving.

• When it is moving in a straight line at constant speed.

• When it begins to slow down.

• When it comes to a stop.

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NGSS.MS-PS2-2

Jackson compared the acceleration of a baseball and a marble when dropped from the same height at the same time. He conducted three trials, each done the exact same way. Why did he repeat his experiment?

• To see whether his results were reliable.

• To follow the rules of the scientific method.

• To try doing the experiment several different ways.

• To keep trying to get the result he was looking for.

Ava has designed an experiment to show how varying the amount of force used on an object will change the acceleration of the object. She plans to move a cat toy by blowing into a straw with a small opening and then into a straw with a large opening. Which law of science is Ava's experiment attempting to prove?

• The greater the mass of the object, the smaller its change in motion.

• Objects with greater mass have more inertia than objects with less mass.

• The greater the force applied, the greater the change in motion for a given mass.

• An object has no acceleration if it moves in a straight line.

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NGSS.MS-PS2-2

Keisha wants to design an experiment that tests how the force of friction affects the kinetic energy of a toy car. Which of the following designs would be best?

• Gather four different toy cars. Send one car down a smooth ramp, ad time how long it takes to reach the bottom. Repeat this procedure with the other three cars.

• Gather four different toy cars. Send two cars down a smooth ramp at the same time to determine which car reaches the bottom first. Repeat this procedure with the other two cars.

• Use one toy car. Send it down a smooth ramp and time how long it takes the car to reach the bottom. Repeat the procedure three more times, covering the ramp first with sandpaper, then with foil, and finally with paper towels.

• Use one toy car. Send it down a smooth ramp, and time how long it takes the car to reach the bottom. Repeat this procedure three more times, but change the angle of the ramp each time.

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NGSS.MS-PS2-2

NGSS.MS-PS3-1

NGSS.MS-PS3-5

Magnets exert forces on objects from a distance.

• true

• false

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NGSS.MS-PS2-3

NGSS.MS-PS2-5

Friction exerts forces on objects from a distance.

• true

• false

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NGSS.MS-PS2-5

Gravity exerts a force on objects by contact.

• true

• false

Tags

NGSS.MS-PS2-5

Which of the following is a contact force?

• electric

• friction

• gravity

• magnetic

A car runs out of gas while moving forward on a flat, straight road. The car keeps rolling for a while because ____.

• gravity pulls it forward

• it still has force

• it has acceleration

• it has inertia