Unit 6 Review

Describe a balanced force.

• A balanced force is when unequal forces act on an object, resulting in movement.

• A balanced force causes an object to speed up in one direction.

• A balanced force is when equal forces act on an object in opposite directions.

• A balanced force is the result of friction acting on a stationary object.

Answer explanation

A balanced force occurs when equal forces act on an object in opposite directions, resulting in no net force and no change in motion. This is why the correct choice describes balanced forces accurately.

Describe an unbalanced force

• An unbalanced force is always equal to the weight of an object.

• An unbalanced force is a force that causes an object to change its state of motion.

• An unbalanced force is a force that does not affect an object's motion.

• An unbalanced force is a force that acts in the opposite direction of motion.

Answer explanation

An unbalanced force is a force that causes an object to change its state of motion. This means it can accelerate, decelerate, or change direction, unlike balanced forces which keep an object at rest or moving at a constant speed.

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NGSS.MS-PS2-2

How do you find total net force? (aka sum force)

• Add all of the forces together.

• Add all of the forces on one side. Add the forces on the opposing side. Subtract the lower sum from the higher sum.

• Total net force is the product of the forces acting in opposite directions.

• Divide the forces.

Answer explanation

To find the total net force, add the forces acting in one direction and the forces acting in the opposite direction, then subtract the smaller sum from the larger sum. This method accurately calculates the net force.

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NGSS.MS-PS2-2

The student is pulling on a wall with a force of 225 newtons. However, neither the student nor the wall is moving. Which statement best explains why there is no movement? 

• The forces are balanced, resulting in no movement.

• The wall is pushing back with greater force.

• The student is not applying enough force.

• The wall is too heavy to move.

Answer explanation

The forces are balanced because the student pulls with 225 newtons, and the wall exerts an equal and opposite force. This equilibrium results in no movement, confirming that the correct choice is that the forces are balanced.

What direction is the man falling and with how much force?

• The man is falling downwards with a force of 1400N.

• The man is falling sideways with a force of 400N.

• The man is floating downwards with no force acting on him.

• The man is falling downwards with a force of 600N.

Answer explanation

The correct choice states that the man is falling downwards with a force of 600N. This aligns with the principles of gravity, where objects fall downwards due to gravitational force, which in this case is quantified as 600N.

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NGSS.MS-PS2-2

Objects with ______ mass have more inertia.

• equal

• more

• less

• no

Answer explanation

Objects with more mass have greater inertia, meaning they resist changes in their state of motion more than lighter objects. Therefore, the correct choice is 'more'.

Tags

NGSS.MS-PS2-2

__________ is an objects resistance to motion.

• friction

• momentum

• velocity

• inertia

Answer explanation

Inertia is the property of an object that resists changes to its state of motion. It explains why an object at rest stays at rest and an object in motion stays in motion unless acted upon by an external force.

Which of the following images illustrated balanced forces?

• 
• 
• 
• 

Riley hits a hockey puck on a flat, frictionless sleet of ice. The puck travels at 4m/s. Describe the motion of the puck when Riley stopped applying force and explain why this took place.

• The puck continues to move at 4 m/s in a straight line.

• The puck starts moving in a circular path.

• The puck comes to a complete stop immediately.

• The puck accelerates to 10 m/s after Riley stops applying force.

Answer explanation

The puck continues to move at 4 m/s in a straight line because, in the absence of friction or any other forces, it maintains its velocity due to Newton's first law of motion, which states that an object in motion stays in motion.

Tags

NGSS.MS-PS2-2

An object ______ will stay at rest until acted on by an _________.

• in motion, internal force

• at rest, gravitational pull

• moving, magnetic field

• at rest, unbalanced force

Answer explanation

The correct choice is 'at rest, unbalanced force' because an object at rest will remain so until an unbalanced force acts on it, in accordance with Newton's first law of motion.

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NGSS.MS-PS2-2