Unit 2 Force and Motion 6th Grade

Types of Forces

Measuring Forces

Force Pairs

Sun Moon and Earth

100

Each sentence describes the effect of a force.

1. A baseball thrown into the air comes back down again.

2. A volleyball player spikes a ball over the net.

3. Water pushing against a swimmer as they move through the water.

4. A tennis ball comes up from the ground after it is bounced.

5. The needle in a compass points toward the North Pole.

Which correctly pairs each effect with the force that causes it?

A. 1: Magnetism; 2: Normal; 3: Gravity; 4: Friction; 5: Applied

B. 1: Gravity; 2: Applied; 3: Friction; 4: Normal; 5: Magnetism

C. 1: Applied; 2: Friction; 3: Normal; 4: Magnetism; 5: Gravity

D. 1: Friction; 2: Magnetism; 3: Applied; 4: Gravity; 5: Normal

B. 1: Gravity; 2: Applied; 3: Friction; 4: Normal; 5: Magnetism

100

Two workers at a furniture store are moving a couch to another display. One worker pushes with a force of 150 N and the other pushes with a force of 180 N in the same direction.

What is the net force exerted on the couch?

30 N

150 N

180 N

330 N

100

According to Newton’s Third Law, what happens when a runner pushes back against the ground to propel themselves forward?

The ground simultaneously exerts the same amount of force on the runner.

The ground simultaneously exerts twice as much force on the runner.

The ground simultaneously exerts half as much force on the runner.

The ground does not exert any force on the runner.

The ground simultaneously exerts the same amount of force on the runner.

100

A Texas scientist is researching climate in Buenos Aires, Argentina, which is located in the Southern Hemisphere. On the first day of their research, the scientist observes that the sun rises at 8:00 am and sets at 5:50 pm. There is daylight for less than 10 hours. On which of the following dates did the scientist most likely begin their research?

A. March 21

B. June 21

C. September 21

D. December 21

B. June 21

200

A worker pushes a large box across the smooth floor of a warehouse. Four forces, labeled A through D, are shown in the diagram.

Which correctly identifies the forces shown?

Force A: Applied; Force B: Friction; Force C: Gravity; Force D: Normal
Force A: Friction; Force B: Gravity; Force C: Normal; Force D: Applied
Force A: Normal; Force B: Friction; Force C: Applied; Force D: Grav
Force A: Applied; Force B: Normal; Force C: Gravity; Force D: Normal

1. Force A: Applied; Force B: Friction; Force C: Gravity; Force D: Normal

200

Two workers at a furniture store are moving a couch to another display. One worker pushes with a force of 150 N and the other pushes with a force of 180 N in the same direction.

Determine whether the forces acting on the couch are balanced or unbalanced.

The forces are unbalanced because the net force equals zero.

The forces are balanced because the net force does not equal zero.

The forces are balanced because the net force equals zero.

The forces are unbalanced because the net force does not equal zero.

200

Which of the following scenarios are examples of an action-reaction pair of forces?

Select TWO correct answers.

A. a swimmer pushing on the water while the water pushes back on the swimmer

B. a diver pushing down on the diving board while the diving board pushes down on the spring

C. a tennis racquet pushing on a ball while the ball pushes back on the tennis racquet

D. a boy climbing up a ladder and holding onto the rails while climbing

E. a girl flying into the air after pushing down on a trampoline while the force of gravity pulls her back down

A. a swimmer pushing on the water while the water pushes back on the swimmer

C. a tennis racquet pushing on a ball while the ball pushes back on the tennis racquet

200

The gravitational pull of the moon has a ______ impact on Earth’s ocean tides than the gravitational pull of the sun because the sun is ______ Earth.

Choose the terms that best complete the sentences.

A. greater; farther from

B. greater; closer to

C. lesser; larger than

D. lesser; smaller than

A. greater; farther from

300

Choose the answers that describe the changes to the scenario that would affect Forces B and C. Select all that apply.

A. Objects are added to the box to make it much heavier.

B. The worker is replaced with someone stronger.

C. The worker pushes the box over an uneven or rough floor.

D. Objects are removed from the box to make it much lighter.

A. Objects are added to the box to make it much heavier.

C. The worker pushes the box over an uneven or rough floor.

D. Objects are removed from the box to make it much lighter.

300

A pet owner takes his dog out in the morning for exercise. The dog is happy to be out and pulls forward on his leash at a force of 100 N. The owner keeps the dog close by gently pulling backward on the leash with a force of 110 N.

Calculate the net force on the leash.

110 N backward

210 N forward

10 N backward

0 N

10 N backward

300

What is the equal and opposite force for the force of your hand pulling on the rope as described by Newton's third law?

A Friction of the ground on your shoes in the same direction

B Rope pulling on your hand in the opposite direction

C Rope pulling your friend's hand in the same direction

D Friend pulling on the rope in the opposite direction

B Rope pulling on your hand in the opposite direction

300

The effect of gravitational force on tides in Earth’s oceans is stronger when the ______ are ______. The result is referred to as _________ .

Choose the terms that best complete the sentences.

A. moon and Earth; not aligned; a spring tide

B. sun and Earth; aligned; a spring tide

C. sun and moon; aligned; a spring tide

D. sun and moon; not aligned; a neap tide

C. sun and moon; aligned; a spring tide

400

Magnetism is a force that can be either a push or pull. Magnetic force is exerted when a magnet interacts with or with another magnet. In the diagram, two bar magnets are placed near each other with the north pole of one facing the south pole of the other. Since the magnets are placed with their north and south ends near each other, the magnetic force between them will be .

Which terms best complete the paragraph?

noncontact; any object; repulsive

noncontact; metal; attractive

contact; any object; attractive

contact; metal; repulsive

noncontact; metal; attractive

400

Which of the following are indicators that an object is experiencing balanced forces?

Select TWO correct answers.

A.An object is changing its direction.

B.An object is moving at a constant speed.

C.An object is stationary.

D.An object is speeding up.

E.An object is slowing down.

B.An object is moving at a constant speed.

C.An object is stationary.

400

A boy and a dog are both pulling oppositely on the same bone when the boy pulls as hard as he can.

What is the equal and opposite force for the force of the boy pulling on the bone as described by Newton's third law?

A Friction of the ground on the boy’s shoe

B Bone pulling the dog in the same direction

C Dog pulling on the bone in the opposite direction

D Bone pulling on the boy in the opposite direction

400

Which statements describe a neap tide? Select all that apply.

A. Tide with the greatest difference between high and low tide

B. Earth, sun, and moon aligned

C. Tide with the smallest difference between high and low tide

D. Gravitational forces of the sun and moon on Earth are perpendicular to each other

C. Tide with the smallest difference between high and low tide

D. Gravitational forces of the sun and moon on Earth are perpendicular to each other

500

Choose the change(s) that can affect the strength or direction of the magnetic force between the magnets in the diagram. Select all correct answers.

Orientation of magnets

Strength of magnets

Distance between magnets

Mass of the magnets

Orientation of magnets

Strength of magnets

Distance between magnets

500

A satellite orbits the Earth at a constant speed. The forces that maintain the constant speed must be -

A. balanced

B. unbalanced

C. cancelled

D. displaced

A. balanced

500

A track athlete jumps over a hurdle.

What is the equal and opposite force for the force of the athlete pushing on the ground as described by Newton's third law?

Force of gravity of athlete pulling up on the Earth

Force of the athlete’s arms swinging up as he jumps

Force of gravity from Earth pulling down on the athlete

Normal force of the ground pushing the athlete up

500

Which of the following does not affect the seasons on Earth?

A. The Earth’s revolution around the sun

B. The tilt of Earth’s axis of rotation

C. The moon’s revolution around Earth

D. The changing distance between Earth and the sun

C. The moon’s revolution around Earth