forces

introduction to forces

a force is a push or pull and is measured in newtons (N), named after Sir Isaac Newton. Forces are measured using a newton meter and have both a size and a direction.
You cannot see a force but often you can see what it does. Forces can make things movie, speed up or make already moving objects slow down. Change the direction they are moving in, and change the shape of things



balanced and unbalanced forces

Balanced forces are forces that act on an object but cancel each other out because they are the same size and are acting in opposite directions. This means that there will be no net force on the object.  If there are forces acting on an object that is acting in the opposite direction and are different sized they are said to be unbalanced.


friction

 Friction is a force that occurs when two materials rub together. Friction always acts to oppose ( prevent or stop ) the movement of an object. Drag is another name for the friction that occurs when an object moves through a fluid, such as air or water. The effects of friction can be reduced if the surfaces of the two materials are lubricated, ( with water, etc). Friction can be increased by making one or more of the surfaces rougher or by pressing them together more strongly


calculating speed

 Speed is a measure of how far an object can travel in a certain amount of time. We often use kilometers
per hour in everyday life, However. scientists generally use meters per second as it is a more accurate measure of speed. To calculate speed, we need to know two variables - distance traveled and time is taken to travel the distance.