Force and Motion

According to Newton's third law of motion, if someone jumps off a skateboard, the skateboard will roll backward because -

• The force that sent the person forward there is an equal force pushing back on the skateboard.

• The air resistance on the person is great and the friction on the skate board is small

• the pull of gravity on the person is the same as on the skateboard, regardless of size

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

Tags

NGSS.MS-PS2-1

Which two characteristics are most useful for determining its elastic potential energy of a stretched rubber band?

• The length to which the rubber band is stretched and the force used to stretch it

• The mass of the rubber band

• The length to which the rubber band is stretched and the mass of the rubber band

• The force used to stretch the rubber band and its height above the ground

Two object are sitting on a table. Which of the two objects will have the greater gravitational potential energy?

• The larger object

• The smaller object

• The object with more mass

• The object with less mass

Tags

NGSS.MS-PS2-4

NGSS.MS-PS3-2

An amusement park ride uses electricity to make its motor spin. The ride also makes noise and lights up. Which observation of the amusement park ride demonstrates the law of conservation of energy?

• The amount of energy used by the amusement park ride is greater than a water-log ride.

• The amount of electrical energy used equals the total amount of mechanical, sound, and light energy produced.

• The amusement park ride only uses energy when it has a full group of riders on it.

• The amount of energy used by the ride is less than the total amount of energy produced as the motor spins.

Tags

NGSS.MS-PS3-5

Which of the following is true of the relationship between kinetic and potential energy?

• When a system loses kinetic energy, it loses potential energy

• As kinetic energy decreases, potential energy decreases

• When a system gains kinetic energy, it loses potential energy

• As kinetic energy increases, potential energy increases.

Tags

NGSS.MS-PS3-5

Which of the surfaces investigated showed the greatest amount of friction?

• A

• B

• C

• D

Two students pull on a rope in opposite directions but neither of them move.

Which of the following best describes the forces being applied in this situation?

• The forces are balanced and the net force is positive

• The forces are unbalanced

• The net forces have the greatest gravitational potential energy

• The forces are balanced, and the net force is zero

Two magnets pull on each other. What would make the magnets pull with less force?

• Use two stronger magnets

• Add heat to one magnet

• Turn both magnets around

• Move the magnets further apart

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

16N ------->[box]<-------- 12N

• 28 N <------------

• 4 N <----------

• 4 N --------->

• 28 N ------------>

Tags

NGSS.MS-PS2-2

A book rests on a table. The force of gravity pulls down on the book with a force of 20 newtons. What prevents the books from accelerating downward at 9.8 m/sec?

• The table presses back up on the book with an equal and opposite force of 20 N

• The table presses back up on the book with a force greater than 20 N

• The table and the book together are accelerating downwards at 9.8 m/sec

• The inertia of the book holds it up

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4