Gravity and Friction

Which of these describes the gravitational force from a planet?

• large and pulls objects toward itself

• small and pulls objects toward itself

• large and pushes objects away from itself

• small and pushes objects away from itself

Tags

NGSS.HS-PS2-4

Which pair of objects has the largest gravitational force?

• marble and car

• marble and baseball

• car and bowling ball

• There is no gravitational force between any of these pairs of objects.

Tags

NGSS.MS-PS2-4

Kirey is moving heavy furniture by sliding it across the floor. He puts a blanket underneath the furniture. Why did this help him?

• The blanket protects the side of the furniture from bumping against the wall.

• The blanket reduces the gravitational force between the furniture and the floor.

• The friction is larger between the blanket and the floor than between the furniture and the floor.

• The friction is smaller between the blanket and the floor than between the furniture and the floor.

Two basketballs are sitting 1 m apart and are not moving. Which best explains why the gravitational force does not cause them to move?

• No gravitational force exists between the two objects because they are not touching.

• The gravitational force between the two objects is weak because they are 1 m apart.

• No gravitational force exists between the two objects because their masses are small.

• The gravitational force between the two objects is weak because their masses

  are small.

Tags

NGSS.MS-PS2-4

If someone drops a cup, it falls to the ground. Why doesn’t the gravitational force between the person’s hand and the cup keep the cup from falling?

• The cup does not experience any gravitational force because it is not a planet.

• The gravitational force between the hand and the cup is so strong that it pushes the cup down.

• There is no gravitational force between the hand and the cup, so Earth’s gravitational force pulls the cup down.

• There is a gravitational force between the hand and the cup, but Earth’s gravity is stronger, so Earth’s gravity pulls the cup down.

Tags

NGSS.MS-PS2-4

In which situation is it better to have

low friction?

• a skydiver uses a parachute

• a student walks down a hallway

• a ladder leans against the wall

• a hockey puck slides toward the goal

Planets A and B are both the same size, but planet B has three times the mass of planet A. How does the weight of an object compare on the two planets?

• The weight of an object is the same on

  both planets.

• The weight of an object is three times larger on planet A.

• The weight of an object is three times larger on planet B.

• The weight of an object will depend on more factors than just the weight and size of the planet.

Tags

NGSS.MS-PS2-4

The object pushes back

• contact force

• action force

• reaction force

• net force

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NGSS.MS-PS2-1

The direction of force

• What does the head of an arrow indicate

• reaction force

• What does the length of an arrow indicate

• net force

Forces acting on an object that combine and form a net force that is not zero.

• Unbalance force

• balanced force

• circular motion

• noncontact force

Tags

NGSS.MS-PS2-2