# What is a push and pull Force?

## Summary

A force is a push or pull upon an object resulting in an interaction between the two objects. When there is an interaction, there is a force. Thus forces only exist when there is an interaction.

Objects have mass. A force of a push or pull will cause it to change velocity.

Video on Push and Pull

Sometimes objects don’t change direction or move. This is due to forces that are of equal size in opposite direction. This force is balanced and would not cause a movement. It is an unbalanced force that causes an object to move or change direction.

## Upthrust Force

Object on water experience a force that pushes an object up and makes it seem to lose weight in the fluid. Upthrust is also called buoyancy and it explains a boat floating on water or a swimmer moving in the water. Upthrust also occurs in air. A helium balloon floating in the air also experience the upthrust force.

### Use of Forces

Forces can be used to twist or turn objects.

Objects will spin quicker if the force is greater.

#### Activities

Synonyms for twist/turns, push and pull. Make a list of words that are the synonym for twists/turns, push and pull. Compare your answers. Click on the link here.

Make a list of things you can twists/turn. What happens to the objects that you can twist and turn.

Push and Pull. Look around your house and find items that would do a push and pull motion. Then sort the items according to push and pull. For example you may find elastic, puzzles, etc.

## Types of Forces

Interactions between objects can occur on physical contact or as a result of non-physical contact between objects.

### Activity

Observe the Force. Create you own experiment to show how objects can move faster, come to a rest, or change direction.

### Types of Forces that involves Physical Contact

#### Frictional force

A force that is exerted by a surface as an object moves across it or makes an effort to move across it.

#### Tension Force

A tension force is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.

#### Normal Force

Normal force is support force. It the force exerted upon an object that is in contact with another stable object.

#### Air Resistance Force

This is a special type of frictional force that acts upon objects as they travel through the air.

#### Applied Force

The force applied to an object by a person or another object is applied force.

#### Spring Force

A spring force is a force that is exerted by a compressed or stretched spring upon any object that is attached to it.

### Types of forces that involves Action-at-a-distance

#### Gravitational Force

This is the force with which the earth, moon or other massive object attracts another object towards itself.

Gravitational force is the force that allows the ball to come back down.

#### Electrical Force

There is a force exerted between any two charged objects. This is electrical force.

#### Magnetic Force

This is an attraction or repulsion that arises between electrically charged particles because of their motion.