Forces and Motion

Four solid balls, each with a different mass, are moving at the same speed. Which ball would require the most force to stop its motion?

• ball with a mass of 5 kg

• ball with a mass of 10 kg

• ball with a mass of 15 kg

• ball with a mass of 20 kg

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NGSS.MS-PS2-2

Which graph represents an object that is decreasing in speed?

• a

• b

• c

• d

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NGSS.MS-PS3-1

Which best describes the speed of a ball as it is thrown straight up into the air and comes back down?

• The ball goes up at a constant speed, stops, then comes down at a constant speed.

• The ball goes up at a constant speed, stops, and increases speed as it comes down.

• The ball goes slower and slower as it goes up, stops, and then goes faster and faster as it goes down.

• The ball goes slower and slower as it goes up, stops, and then comes down at a constant speed.

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NGSS.MS-PS2-4

NGSS.MS-PS3-5

A student uses a rubber to launch the four objects shown in the table. If the student pulls the rubber band back the same amount each time, which object will most likely move the fasted when launched?

• paper clip

• piece of paper

• eraser

• rubber ball

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

This is the free-body diagram of a box. Someone is trying to push the box, but it is too heavy. Which arrow represents gravity?

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS2-4

The diagram shows a blue object in different fields. The arrow represents a force acting on the object in each field. Move a label to each blank box to identify the property that could change so that the force acting on the object is altered. Use only one label in each blank box. You do not need to use all of the labels. 

b

c

Mass

Charge

Magnetism

Volume

Answer explanation

Gravity is affected by the size of objects (mass) and the distance between objects.

The electric field strength is dependent upon the quantity of charge and the distance from the charge.

Tags

NGSS.MS-PS2-4

A box is moving toward the right. Two forces act on the box: a force pushing the box to the right and a friction force. The two forces acting on the box are shown in the four force diagrams. Identify whether the speed of the box in each diagram will decrease, increase or remain constant.

c

Speed decreases

Speed remains constant

Speed increases

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

When soccer legend Megan Rapinoe kicks the ball,

her ​ (a)   pushes the object right, but ​ (b)   pushes the object left.

• applied force

• friction

• gravity

• normal force

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

A box is moving toward the right. Two forces act on the box: a force pushing the box to the right and a friction force. The two forces acting on the box are shown in the four force diagrams. Identify whether the speed of the box in each diagram will decrease, increase or remain constant.

b

Speed remains constant

Speed increases

Speed decreases

Tags

NGSS.MS-PS2-2

The graph below shows an object’s position in meters (m) over time in seconds (s) as it travels in a straight line. The object starts at rest.

Identify whether there are balanced or unbalanced forces acting on the object during each time interval. 

Between 1-2 seconds ​ (a)  

Between 3-4 seconds ​ (b)  

Between 5-7 seconds ​ (c)  

• Balanced Forces

• Unbalanced Forces

Answer explanation

Remember, if the line is curved, the forces are unbalanced!

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2