# Forces in a block

## Would you like to know more about the physical concept of force, how it works and some of its most important types?

The online force simulations on this page allow us to improve our knowledge about the physical concept of forces, how they act, what effects they produce and how to operate with them.

In physics, a force is defined as an interaction that can change the state of motion or deformation of an object. Force is a vector magnitude. Its unit in the International System is the newton (N). The study of forces is fundamental to understanding physical phenomena and describing the behavior of systems in the universe.

In the following, we will explore different types of forces and their main characteristics.

Gravitational force. This is the force of attraction between two objects with mass. The gravitational force always acts towards the center of mass of the objects and depends on the mass of the objects and the distance between them, following Newton’s law of universal gravitation.

Electromagnetic force. It is responsible for the interactions between electric charges. This force can be attractive or repulsive and acts through electric and magnetic fields. The electromagnetic force is the basis of phenomena such as friction, magnetic force and interactions between atoms and molecules.

Normal force. It acts perpendicular to the contact surface between two objects and is equal and opposite to the force exerted by the object on the surface.

Frictional force. Arises when there is resistance to relative motion between two surfaces in contact.

Tensile force. Occurs in stretched objects, such as ropes or cables, and acts along them.

In summary, the online force simulations on this page will help us to understand what a force is and what are its main characteristics.

## Normal force

This simulation is useful to see what the normal force applied by a surface on a block looks like. What happens to the normal force when the block is pushed down? How are normal force, downward force and weight related?

## Tension

This simulation is useful to see what the tension force on a rope is like when pulling a block upward. What is the sum of the tension and the normal force?

Force is a vector quantity. When several forces act on an object, the resultant force is the vector sum of those forces. Change the modulus and direction of the forces and see how the resultant force changes.

Force is a vector quantity. When several forces act on an object, the resultant force is the vector sum of those forces. See what happens when you move the arms of the “strongman” holding the book.