Newton's Laws and Forces Comprehension

What is Newton's First Law of Motion, and what does inertia mean?

• An object will change its motion unless a force acts on it; Inertia is the tendency to change motion.

• An object will remain at rest or in uniform motion unless acted upon by an external force; Inertia is the tendency to resist changes in motion.

• An object will accelerate if a force is applied; Inertia is the tendency to accelerate.

• An object will stop moving if no force acts on it; Inertia is the tendency to stop.

Answer explanation

Newton's First Law states that an object remains at rest or in uniform motion unless acted upon by an external force. Inertia refers to the object's resistance to changes in its state of motion, making the second choice correct.

What is the difference between balanced and unbalanced forces?

• Balanced forces cause acceleration; Unbalanced forces cause no change in motion.

• Balanced forces are unequal; Unbalanced forces are equal.

• Balanced forces cancel each other out and cause no change in motion; Unbalanced forces create a net force that causes acceleration.

• Balanced forces always act in the same direction; Unbalanced forces act in opposite directions.

Answer explanation

Balanced forces are equal and opposite, canceling each other out, resulting in no change in motion. Unbalanced forces create a net force, leading to acceleration and a change in motion.

What happens to kinetic energy in inelastic collisions?

• It is completely conserved.

• It is lost as heat and sound.

• It increases.

• It remains unchanged.

Answer explanation

In inelastic collisions, kinetic energy is not conserved. Instead, some of it is transformed into other forms of energy, primarily heat and sound, which is why the correct answer is that it is lost as heat and sound.

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What is the definition of acceleration?

• The speed of an object.

• How fast an object's speed changes, divided by time.

• The distance an object travels.

• The force applied to an object.

Answer explanation

Acceleration is defined as how fast an object's speed changes over time. This means it measures the rate of change of velocity, making the second answer choice the correct one.

Which type of force involves two or more forces that are equal in strength but opposite in direction, causing no change in motion?

• Contact Force

• Gravitational Force

• Balanced Force

• Inertia

Answer explanation

Balanced forces are equal in strength and opposite in direction, resulting in no change in motion. This is why the correct answer is Balanced Force, as it perfectly describes the scenario presented in the question.

What is the process of moving energy from one object, place, or system to another?

• Energy Transformation

• Energy Transfer

• Kinetic Energy

• Gravitational Potential

Answer explanation

The process of moving energy from one object, place, or system to another is called Energy Transfer. This term specifically describes the movement of energy, unlike Energy Transformation, which refers to changing energy from one form to another.

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What is a push or a pull that, if nothing stops it, will change how an object moves?

• Friction

• Force

• Inertia

• Gravitational Potential

Answer explanation

A force is a push or pull that can change an object's motion. Unlike friction or inertia, which resist or maintain motion, a force actively alters how an object moves when applied.

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What is a contact force that resists sliding motion between objects that are touching?

• Gravitational Force

• Inertia

• Friction

• Balanced Force

Answer explanation

Friction is the contact force that opposes the sliding motion between two surfaces in contact. It acts to resist movement, making it the correct answer to the question.

What is the amount of work needed to move an object against gravity to a specific position from a starting position?

• Kinetic Energy

• Gravitational Potential

• Energy Transfer

• Friction

Answer explanation

The work needed to move an object against gravity to a specific position is known as Gravitational Potential energy. It quantifies the energy stored due to an object's position in a gravitational field.

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What is an object's natural tendency to resist changes in how it's moving?

• Energy

• Inertia

• Force

• Friction

Answer explanation

An object's natural tendency to resist changes in its motion is called inertia. It describes how an object will remain at rest or in uniform motion unless acted upon by an external force.