Intro to Forces

A box has two forces acting on it. Once force is 100 N upward. Another force is 50 N downward. What is the net force of the box?

• 50 N downward

• 50 N upward

• 100 N upward

• 100 N downward

Tags

NGSS.MS-PS2-2

Melanie watched the path a baseball followed after a pitcher threw it. She noticed that the ball traveled horizontally away from the pitcher as well as downward toward the ground. What force caused the ball to accelerate in the downward direction when it was thrown?

• applied force

• air resistance

• electrical force

• gravitational force

Tags

NGSS.MS-PS2-4

Why is the friction force considered to be a contact force?

• Friction affects only solid objects.

• Friction always acts in the same direction.

• Friction is produced when objects slide past one another.

• Friction acts in a direction opposite to the direction of an object's motion.

Why is the magnetic force considered to be a noncontact force?

• Magnets must be large in size in order to exert a force that is strong enough to notice.

• Magnets push each other apart to increase the distance between them.

• Magnets do not have to touch each other to experience a force.

• Magnets must be far apart in order to exert a force.

Tags

NGSS.MS-PS2-5

The diagram shows the forces acting on a box. What is the the vertical net force (up and down)?

• 50 N up

• 50 N down

• 0 N no movement

• 0 N down

The diagram shows the forces acting on a box. Predict how the box will move.

• up and left

• down and left

• only right

• only left

Tags

NGSS.MS-PS2-2

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

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

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

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

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

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 will depend on more factors than just the weight and size of the planet.

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

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

• The weight of an object is the same on

  both planets.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

Which force pulls objects towards the center of the earth?

• Gravity

• Friction

Tags

NGSS.MS-PS2-4