Physics Chapter on Force and Motion

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Questions and Answers

What does a one newton of force signify?

The force that can give a 1 kg body an acceleration of 1 m/s².

The force that can give a 1 kg body an acceleration of -9.8 m/s². (correct)

The force that can give any mass an acceleration of 1 m/s².

The force that can give any mass an acceleration of -9.8 m/s².

Which situation demonstrates balanced forces acting on an object?

A coin moves in decreasing velocity as it is tossed in the air.

A ball is freely falling from a building.

A boulder is speeding up while rolling down an incline.

A box rests above a platform. (correct)

Which of the following statements is TRUE about unbalanced forces?

It changes the state of motion of objects. (correct)

It makes an object move at constant velocity.

It keeps an object at rest.

It results in uniform motion.

What classification of force does not require physical contact between objects?

Non-Contact Force Signup and view all the answers

What force is present when an object exerting a force touches another object?

Contact Force Signup and view all the answers

What does net force refer to?

The vector sum of all forces acting on an object, including directions. Signup and view all the answers

If two persons are pushing a box horizontally, what can be inferred about its motion?

The box is experiencing balanced forces horizontally. Signup and view all the answers

In a free body diagram (FBD), which statement is TRUE about the forces acting on a box?

The box is accelerating to the right due to the applied force. Signup and view all the answers

Which of the following statements best describes unbalanced forces?

They lead to a change in an object's state of motion. Signup and view all the answers

What does the term 'net force' specifically refer to?

The sum of all forces acting on an object in a single direction. Signup and view all the answers

What unit is used for measuring force in the International System of Units (SI)?

Newton Signup and view all the answers

In which situation would an object likely have greater inertia?

An object with a high mass at rest. Signup and view all the answers

Which of the following is true about balanced forces?

The object moves with a constant velocity where the net force is zero. Signup and view all the answers

Which law states that an object at rest will remain at rest unless acted on by an unbalanced force?

Newton's First Law of Motion Signup and view all the answers

If the net force on an object is zero, which of the following can be concluded?

The object is moving at a constant speed. Signup and view all the answers

When forces are described as non-contact forces, what does this imply?

The forces operate without physical interaction between the objects. Signup and view all the answers

What happens to the acceleration of an object if the net force acting on it increases, according to Newton's Second Law of Motion?

It increases. Signup and view all the answers

Which of the following BEST describes the role of friction?

It opposes the relative motion of objects in contact. Signup and view all the answers

Study Notes

What is Force?

A force is a push or a pull that results from an interaction between objects.
It is a vector quantity, meaning it has both magnitude and direction.
The standard unit of force is the Newton (N).

Types of Forces

Contact forces: Forces that require physical contact between objects, such as pushing a box or friction.
Non-contact forces: Forces that act without direct contact, such as gravity, magnetism, and electric forces.

Newton's Laws of Motion

Newton's First Law (Law of Inertia): An object at rest will stay at rest, and an object in motion will stay in motion at a constant velocity unless acted upon by an unbalanced force.
- Inertia is the tendency of an object to resist changes in its motion.
- The more massive an object is, the greater its inertia.
Newton's Second Law (Law of Acceleration): The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
- In equation form: F = ma (where F is force, m is mass, and a is acceleration)
Newton's Third Law (Law of Action-Reaction): For every action, there is an equal and opposite reaction.
- When one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

Net Force

The sum of all forces acting on an object, taking into account both magnitude and direction.
When net force is zero, the object is in equilibrium and its state of motion remains unchanged.
When net force is not zero, the object accelerates in the direction of the net force.

Balanced and Unbalanced Forces

Balanced forces: Forces acting on an object that cancel each other out, resulting in a net force of zero.
Unbalanced forces: Forces acting on an object that do not cancel each other out, resulting in a net force that is not zero.

Friction

A force that opposes motion between surfaces in contact.
Friction can be static (opposing the start of motion) or kinetic (opposing motion that is already occurring).

Other Important Concepts

Acceleration: The rate of change of velocity over time.
Velocity: The rate of change of position over time.
Equilibrium: A state where the net force acting on an object is zero, and the object is either at rest or moving at a constant velocity.

Example Calculations

Force needed to accelerate a 1 kg object at 1 m/s²: Using F=ma, F = (1 kg)(1 m/s²) = 1 N
Net force on a stationary box with multiple forces acting on it: Sum all the forces, accounting for their directions. If the sum is zero, the net force is zero and the box remains at rest.
Acceleration of an object when a specific force is applied: Using F=ma, rearrange to solve for a: a = F/m

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Description

Explore the fundamental concepts of force, including contact and non-contact forces, along with Newton's Laws of Motion. This quiz will help you understand how forces influence the motion of objects and the principles behind them. Test your knowledge on these key physics topics.