Balanced and unbalanced forces

Two classes of students line up for a tug of war. If both classes have the same number of students on a team, what other factor is very important so one team can win?

• A. total mass of each team

• B. condition of the ground

• C. age of students on each team

• D. height of students of each team

Answer explanation

The total mass of each team is crucial in a tug of war, as a heavier team can exert more force and resist being pulled. While other factors like age and height matter, mass directly impacts the outcome.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Forces that are equal in strength and opposite in direction are:

• balanced forces

• unbalanced forces

• always result in motion

• always the result of motion

Answer explanation

Balanced forces are equal in strength and opposite in direction, resulting in no change in motion. This means that the object remains at rest or continues to move at a constant speed.

Seth and Leah each kick a soccer ball. Leah's ball goes farther than Seth's. What must be true of the force of Leah's kick?

• A. Leah's force can not be compared to Seth's force.

• B. Leah kicked the soccer ball with more force than Seth.

• C. Leah kicked the soccer ball with less force than Seth.

• D. Leah kicked the soccer ball with the same force than Seth.

Answer explanation

Since Leah's ball goes farther than Seth's, it indicates that Leah must have applied more force in her kick. Therefore, the correct choice is B: Leah kicked the soccer ball with more force than Seth.

Tags

NGSS.MS-PS2-2

The image shows two opposite forces acting on a box. What can we say that is true about the effect of the forces on the box?

• A) The box will move to the right.

• B) The box will move to the left.

• C) The box will not move.

• D) The box will move up.

Answer explanation

The box experiences two opposite forces that are equal in magnitude. According to Newton's first law, if the net force is zero, the box will not move. Therefore, the correct answer is C) The box will not move.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

To investigate the effects of balanced and unbalanced forces, Jose and Gina test various objects and record the results. For this investigation, they stand on opposite sides of a large 10-pound wooden box and push against it toward one another. Jose pushes with 20 pounds of force and Gina pushes with 15 pounds of force. Which BEST describes what will happen?

• The box will not move.

• The box will move toward Gina.

• The box will move toward Jose.

• The box will lift off the ground.

Answer explanation

Jose exerts 20 pounds of force while Gina exerts 15 pounds. The net force is 5 pounds toward Jose, causing the box to move in his direction.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

For science class, your teacher gives you and your partner a ball. She asks you to figure out a way to balance forces that you apply to the ball. How do you and your partner show this?

• Both of you pull with equal force on the same side of the ball.

• Both of you push with equal force on the same side of the ball.

• Both of you pull with equal force on opposite sides of the ball.

• One person pulls and one person pushes with equal force on opposite sides of the ball.

Answer explanation

To balance forces, both partners should pull with equal force on opposite sides of the ball. This creates equal and opposite forces, resulting in a net force of zero, which maintains balance.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Patrick was riding his new skateboard in the skate park. All of a sudden, he hit a small rock and his skateboard stopped. Patrick ended up falling off his skateboard and broke his arm. The small rock created an opposing force and made the skateboard stop because:

• the forces were pulling.

• the forces were pushing.

• the forces were balanced.

• the forces were pushing and pulling.

Answer explanation

The small rock created an opposing force that stopped the skateboard. When the skateboard hit the rock, the forces acting on it became balanced, leading to a stop and causing Patrick to fall.

Tags

NGSS.MS-PS2-2

Both the red stickman and blue stickman are pushing the box in front of a tree. What is this diagram showing?

• A. The red stickman is applying more force.

• B. The blue stickman is applying more force.

• C. The force applied on the box is balanced.

• D. They are both applying the same amount of force.

Answer explanation

The diagram shows both stickmen pushing the box with equal force, resulting in a balanced force. Therefore, options C and D are correct, indicating that the forces are equal and balanced.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

How will this object move? 

• It won't move. 

• It will move to the right. 

• It will move to the left. 

• It will move in both directions. 

Answer explanation

The object won't move because there are no forces acting on it or it is in a state of equilibrium. Therefore, the correct answer is that it won't move.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Forces that have a net force of zero ( the object is still).

• Balanced force

• Unbalanced force

Answer explanation

Balanced forces occur when the net force on an object is zero, meaning all forces acting on it cancel each other out. This results in the object remaining still or in constant motion.

Tags

NGSS.3-PS2-1