Momentum and Energy

MOMENTUM

Definition: 

Momentum is a vector describing objects in motion according to their mass and their velocity.

Calculate:

To calculate momentum you need to know the mass and velocity of an object. So Momentum= mass * velocity. For example, to describe the momentum of a semi truck you need its mass which is 36,287.39 kg (80,000 lbs) and its velocity which is 26.8824 m/s(60 miles/h). Then you multiply them so

 36,287.39kg * 26.8824m/s= 9,754,921,329.36 kg*m/s

Units:

kilograms * meters/second or kg*m/s

Impulse:

Impulse is defined as force with respect to time, essentially it is the change in the momentum of an object.

Conservation of Momentum:

Essentially what the law of Momentum Conservation is that during a transfer of momentum, or a collision, the momentum of both objects before is equal to the momentum after the collision, the momentum lost by one object is is the same as the momentum gained by the other object.

ENERGY!

Work:

Work is when a force acts upon an object to cause a displacement of the object. You need a force, displacement, and cause to get work done on an object. Work= force * distance.  

For example if you push a box 6 meters by exerting 12 Newtons of force the work done would be 72 meters * Newtons. The unit for work is meters * newtons which is called a joule so the work done on the box would be 72 Joules. 

Energy:

Is the capacity of a physical system to do work. Energy like mass can neither be created or destroyed. All energy is measured in Joules as well.

Kinetic Energy:

Kinetic energy is the energy of motion. 

Kinetic Energy= 1/2 mass * velocity squared or KE= 1/2mv^2

For Example: The Kinetic Energy of an object that is 40kg and is going 9m/s is 360 Joules because it is currently in motion. 

Potential Energy:

Potential Energy is defined as the energy an object can store according to its position, basically the potential and object has to move. 

Potential Energy according to gravity is the energy stored in an object before is drops into free fall.

Potential Energy =mass * gravity * height or PE = m*g* h

For example, if you push a person with a mass of 60 kg off a cliff that is 10 meters high when gravity= 9.8m/s^2 . So 60kg*10m*9.8m/s^2 which equals 5880 kg*m*m/s^2 which equals 5880 Joules. 

Conservation of Energy:

The conservation of energy is that energy, like mass, can neither be created or destroyed, it can only change, so kinetic energy does not disappear it changes to potential energy of some other type of energy.