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force

Primary Information
Secondary Information

Definition

A force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object to change its speed, direction, or shape. Forces can be applied in different directions, and they can be either large or small.

The SI unit of force is Newton (N). One newton is the force that is needed to accelerate a mass of 1 kilogram by 1 meter per second squared.

There are many different types of forces, including:

  • Gravitational force is the force that attracts objects towards each other.
  • The electric force is the force that attracts or repels charged particles.
  • Magnetic force is the force that attracts or repels magnetic materials.
  • Friction is the force that resists the motion of two objects that are touching.
  • The normal force is the force that pushes back on an object that is resting on a surface.

Forces can be added together to find the net force acting on an object. The net force determines how the object will move.

How can the word be used?

The police used force to disperse the crowd.

force

Different forms of the word

Noun: force, forces.

Adjective: forceful, forcible.

Verb: force, forced, forcing.

Adverb: forcefully.

Etymology

The word "force" is derived from the Old French word force, which means "strength". The Old French word force is ultimately derived from the Latin word fortis, which also means "strength".

Question

What different types of force can you name?

AQA Science Exam Question and Answer

Question:

Explain the concept of force and its role in causing motion or changes in motion. Describe the different types of forces, including contact forces and non-contact forces, and provide real-life examples of each. Discuss the impact of forces on objects, such as balanced forces resulting in no change in motion and unbalanced forces causing acceleration or deceleration.

Answer:

Force is a fundamental concept in physics that describes the push or pull applied to an object, resulting in motion or changes in motion. Contact forces involve direct physical contact between objects, such as pushing a book across a table or pulling a door handle. Non-contact forces, like gravity and magnetism, act at a distance without physical contact.

Real-life examples of forces include friction, which opposes motion and is crucial for walking and driving; gravity, which keeps objects on the ground and determines the motion of planets; and magnetic forces, which attract or repel objects with magnetic properties.

When forces on an object are balanced, there is no change in motion. However, unbalanced forces lead to acceleration or deceleration, causing objects to speed up, slow down, or change direction.

Understanding forces is vital in explaining everyday phenomena and the behaviour of objects in motion, as well as in engineering and designing systems that rely on these principles, like cars, bridges, and space missions.