Laws of motion

• 1st law 


  a resultant force is required to change the motion of an object
• 2nd law 


  If a non zero resultant force acts on an object then it will cause it to accelerate
• the size of a resultant force is directly proportional to the acceleration that it causes
• Inertia is the resistance to a change in velocity
• Inertial mass is a measure of how difficult it is to change an objects velocity
• Large mass has a lot of inertia so requires a big force to change its velocity
• 3rd law


  When 2 objects interact the forces they exert on each other are equal and opposite
• Newtons 3rd law deals with forces on different objects