Science Notes for Systems in Action

Formulas

FG=MG

Force of gravity = mass (kg) x gravity (9.8N)

W=FxD

Work = Force x Distance

MA = Fout

         Fin

Fout = Force output 

Fin = Force input

(Fout always has to be in Newtons)

IMA = Din

          Dout

Din = Distance input

Dout = Distance output

Forces + Input/Output

Contact force: They need to touch the object that pushes and pulls

  • Friction is an example of a contact force

Friction: Friction is a force that opposes the motion of an object. Friction can resist a motion and slow the motion of something down. 

  • If you roll a hockey puck on a wooden floor

Action-at-a-distance: A force that can push or pull an object without touching it. It's also known as non-contact force. 

  • Gravity and magnetism are an example of a Action-at-a-distance

Gravity: An attraction between two objects due to their mass. The amount of attraction relies on the amount of the mass for each object. 

  • When you let go of a ball, it's pulled to the ground by gravity.

The Unit for force: The metric unit for a force is Newton(N). Weight is the force of gravity, measured in (N).

Mass: The amount of matter in an object

  • A tennis ball is lighter than a bowling ball

Weight: The amount of force an object due to gravity

  • Weight means the same thing as the force of gravity

Input Forces: The force that is applied to the machine

  • Fin

  • Person pushing on a car jack

Output Forces: The force the machine applies to the object

  • Fout

  • The jack pushing up the car

Forms of Energy:

Kinetic: When an object is moving

  • Electrical, thermal energy, and sound are example of kinetic energy

Potential: Any energy that can be stored to do work later 

  • Gasoline, chemical energy are example of potential energy

Gravitational potential energy: A potential energy that is able to fall

Function of Machines:

Machine: A machine is any mechanical system that can reduce the force needed to do work

Function of machines: machines make work easier in three ways. Increasing the force that can be applied on an object, increasing the distance over which the force is applied, and by changing the direction of a force.

  • For example Nutcracker: A machine that increasing the force that can be applied on an object

  • Input: press a small amount of force on the handles

Output: The claws opens the nut