Describing Forces

What is gravity?

• a noncontact force

• a frictional force

• a contact force

• a magnetic force

Tags

NGSS.MS-PS2-4

NGSS.MS-PS2-5

Which of these is considered a contact force?

• the force between two charged particles

• the friction between an object and air

• the gravitational pull of a planet

• the force between two magnets

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 are some forces considered to be noncontact forces?

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

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

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

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

Tags

NGSS.MS-PS2-5

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

A bird flies 12.5 meters per second. The wind speed is 4.5 meters per second. What is the speed of the bird when it flies with the wind?

• 17

• 8

• 56.25

• 2.8

A bird flies 12.5 meters per second. The wind speed is 4.5 meters per second. What is the speed of the bird when it flies against the wind?

• 17

• 8

• 56.25

• 2.8

Tags

NGSS.MS-PS2-2

Marek is trying to push a box of sports equipment across the floor. The arrow on the box is a vector showing the force Marek exerts on the box. What forces are acting on the box?

• Applied force

• Applied force and gravitational force

• Applied force, gravitational force, frictional force

• No forces

Tags

NGSS.MS-PS2-2