Newton's laws

Newton's laws

Summary ch 4

Newton's First law

• if an object is at rest it remains at rest, and if an object is in motion it continues with a constant velocity motion unless an unbalanced external force is acting on it

Newton's First law

• if the object is balanced

• if the F net = 0

• no acceleration

• either at rest OR constant velocity

• the other name is law of inertia

Inertia

• the tendency to resist the CHANGE in motion

• if the object is at rest , it remains at rest

• if an object is moving, it continues in a constant velocity motion

• if a person slides to the opposite direction of the turn, this is because of inertia

• 
  

Newton's second law

• the acceleration is directly proportional to the NET FORCE and inversely proportional to the mass.

• F=ma

• 
  

• 
  

Newton's second law

• if the object is not balanced

• if the 

   $F\ net\ne0$  

• there is acceleration

Newton's third law

• for every action, there is an equal and opposite reaction

• forces exist in pairs

• the action-reaction pair acts on two DIFFERENT objects

• F A/B

• F B/A