Force and Newton's Laws

Assuming a frictionless, massless pulley, determine the acceleration of the blocks once they are released from rest.

• mg/(M+m)

• Mg/(M+m)

• Mg/m

• (M+m)g/(M-m)

• (M-m)g/(M+m)

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NGSS.MS-PS2-1

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NGSS.MS-PS2-4

A person who weighs 800 N steps onto a scale that is on the floor of an elevator car. If the elevator accelerates upward at a rate of 2.5 m/s^2, what will the scale read?

• 400 N

• 800 N

• 1000 N

• 1200 N

• 1600 N

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NGSS.MS-PS2-2

NGSS.MS-PS2-4

A 12 kg box slides down a frictionless 30 degree incline from rest. If it starts from rest, after sliding along the incline for 6 seconds the box will have traveled a distance of

• 45 m

• 68 m

• 90 m

• 120 m

• 180 m

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

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A 12 kg box slides down a frictionless 30 incline from rest. If it starts from rest, after sliding along the incline for 6 seconds the speed of the box is

• 30 m/s

• 35 m/s

• 40 m/s

• 50 m/s

• 60 m/s

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

A FedEx delivery person working in the Sears Tower travels to and from various floors on an elevator. During these rides the magnitude of the force pushing up on her feet by the elevator floor exceeds the magnitude of the force pushing down on the floor by her feet:

• When the elevator is moving upward and gaining speed.

• When the elevator is moving upward but losing speed.

• When the elevator is moving upward at constant speed.

• When the elevator is moving down with increasing speed.

• Never. These two forces are always equal in magnitude.

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NGSS.MS-PS2-2

A 25 kg sign is suspended from three cables which are connected point D. These cables are cable AD, cable BD, and cable CD. What is the tension in cable BD (the horizontal cable)?

• 176.775 N

• 250 N

• 353.557 N

• 500 N

• 125 N

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NGSS.HS-PS2-1

Any push or pull is ___________.

• a force

• speed

• acceleration

• velocity

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NGSS.MS-PS2-1

For every force there's an...

• opposite force

• unequal force

• equal force

• equal and opposite force

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NGSS.MS-PS2-1

What is force?

• may the force be with you

• any influence, such as a push or pull, that causes an object to move or change it's speed, direction, or shape

• it is a mass

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NGSS.MS-PS2-2

What is the net force acting on this rope?

• 400 N <--

• 200 N <--

• 300 N <--

• 200 N -->

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NGSS.MS-PS2-2