# Physics FormulasSI Units

Physics formulas are used to work out the variable which is not known by using the variables which we do know, thus creating a physics equations. We can also use them to predict the outcome of certain things. For example if you wanted to launch a rocket you could calculate the amount of thrust you would need to get it to lift off with a certain amount of acceleration.

Physics is a science, but relies heavily on mathematical skills. The main one
being algebra as you need to be able to substitute and rearrange an
equation if necessary.

In physics equations letters can stand for certain things so just like in algebra where letters can stand for numbers. Even though an equation is set out to work out for example force it can be rearranged to show any of the letters in the equation as long as you have the value of the others. F=ma, this equation will give us the force, but we can rearrange it to give us either the mass of the object or acceleration, f/a=m or f/m=a. As long as there is only one unknown we can easily rearrange the equations to give us the answer.

Note: All these physics formulas require you to use SI units
(International System of Units)

## SI units

 Quantity Quantity symbol Unit symbol Mass m kilograms Kg Force F Newtons N distance d meters m speed v Velocity v Pressure p Pascal Pa Work W Joules J Energy E Joules J Time t Seconds s

### Formulas

Ep stands for energy potential which is stored energy. This equation will be able to tell you how much potential energy an object has when it is raised above the ground. Here on earth gravity accelerates all body’s towards the ground at 9.81 m/s^2 if friction is not taken into account.

This equation lets you calculate the amount of kinetic energy an object has.

There is a difference between mass and weight. Mass never changes it is the amount of matter an object is made up of. Weight on the other hand can change since it is the force of gravity acting upon a mass. This is why on the moon you weigh less than you do on earth.

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Pressure referrers to much force is concentrated into an area.

The triangle is the Greek letter Delta and in physics means change. Change in distance divided by the change in time gives you the velocity of an object.

This is one of the more famous physics formulas since it comes from Newton’s second law of motion.

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