Alexa pushes on a door to open it. How does the concept of forces explain why the door opens?

• The door pushed equally hard on Jeanie as she pushed on it.

• The door moved in the opposite direction of the pushing force.

• The door moved in the direction of the pushing force.

• The door opened because of noncontact forces.

Tags

NGSS.MS-PS2-1

To find out if gravity affects all objects the same way, you should plan to investigate the time it takes a penny and a quarter to fall from an equal height. Which step should be a part of your experiment?

• Drop the penny from a height of 2 meters and the quarter from a height of 4 meters.

• Drop the penny from a height of 4 meters and the quarter from a height of 2 meters.

• Drop both the penny and the quarter from a height of 4 meters.

• Drop the penny from a height of 4 meters and throw the quarter from a height of 4 meters.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

Why is friction classified as a contact force?

• Friction can act when objects are not in direct contact.

• Friction acts when two objects rub against each other.

• Friction causes a change in motion.

• None of the other answers answer choices.

Tom is mowing his lawn and the lawnmower is moving forward. Which of the following statements must be true?

• There are no forces acting on the lawnmower.

• The only force acting on the lawnmower is gravity.

• Tom is applying a force on the lawnmower.

• The total force on the lawn mower is zero.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

Rubbing two sticks together to make a fire is an example of

Students test the effect of forces that act from distance. Thus causing an object to move. They discover that two forces have this effect on object. These forces are

• friction and gravity

• Gravity and magnetism

• Magnetism and friction

• gravity and density

Tags

NGSS.MS-PS2-5

When designing an experiment, why is it important to test only one variable?

• Testing one variable explains what caused the change once data has been gathered.

• Testing one variable collects inaccurate data and repeats the investigation more than necessary.

• Testing one variable decreases the reliability of the investigation.

• It is not necessary to test only one variable.

In the picture below one object is attracted to another by

• gravity

• a push

• magnetism

• friction

• a pull

Tags

NGSS.MS-PS2-3

In the science class students learn that friction is the resistance to motion when two objects rub together. The students decide to design an experiment at home to compare frictionon dry and icy surfaces. Which question is the most beneficial for this type of investigation?

• Is it faster to sled down an icy hill or down a rough gravel driveway?

• What is friction?

• What makes ice slippery?

• What effect does the height of the hill have on the distance an object travels.

Tags

NGSS.MS-PS2-2

What force is being tested when an object is forced downward toward the center of Earth?

• Gravity

• Air pressure

• Magnetism

• Friction

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4