# Forces

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• Vectors and Scalars
• a scalar is a line with a direction
• Forces
• Contact and Non-Contact force (and resultant forces)
• A contact force is a force that need two object to toutvh to form/work
• A non-contact force is a force that doesn't need two objects to touch for it to form/work
• A resultant force is the overall force when two or more forces are acting on an object
• Examples of Non-Contact forces
• Magnetic Force
• Electric force
• Gravitational force
• Examples of Contact forces
• Applied force
• Spring force
• Drag force
• Frictional force
• Work done
• Work done = Force * Distance
• W = Joules      F = Newtons d = meters
• The amount of joules 'given'/'done' onto an object
• Parallelogram and resolution of forces
• To resolve a force is doing the opposite of finding out the resultant force
• Draw a rectangle around a perpendicular arrow and find the lengths
• Create parallel lines on opposite sides to find resultant force
• Gravity and center of mass
• Gravity is generally 10 in equations but always use what is given
• The center of mass is the average position of all the masses of an object
• In a simple shape, with equal density the center of mass is in the middle
• Stretching a spring and elasticity
• Extension = extended - original
• Force and extension are proportional until the limit of proportionality
• Elastic potential = 0.5 * spring connstant * extention2
• Force = Extenstion * Spring constant
• A vector is a line with direction and value
• Examples of Scalars
• Length
• Mass
• Power
• Temperature
• Examples of Scalars
• Acceleration
• Weight
• Drag
• Lift
• Thrust
• Examples of Scalars
• Acceleration
• Weight
• Drag
• Lift
• Thrust