Download Newton`s Laws of Motion Newton`s 1st Law • An object moving with

Newton’s Laws of Motion Newton’s 1st Law • An object moving with a constant velocity will remain moving with a constant velocity (including zero velocity which corresponds to “rest”) unless acted upon by an unbalanced force. • The “natural” state of an object is moving with a constant velocity (this includes zero velocity, which corresponds to rest) —Inertia. Inertia ‐ The resistance of an object to changes in its velocity Force ‐ (1) An influence that causes the velocity of an object to change (2) An influence that causes an object to accelerate Forces that are balanced cancel each other. If the forces acting on an object are balanced, the object will behave as though there were no forces acting on it. The object will move with a constant velocity (including zero velocity). Example of Balanced Forces 1. A person standing on the floor: the force of gravity pulls the person down; the floor provides a force that pushes the person up. The force of the floor (also called the Normal Force) cancels the force of gravity. If gravity were the only force acting on the person, the person would fall through the floor. (Draw FBD) 2. A car moving with constant velocity (driving on a straight section of the 401 at 120km/h): the car’s engine provides a forward force; air resistance provides a backward force. If the car’s engine were the only force acting on the car, the car would accelerate forever. (Draw FBD) Newton’s 2nd Law • The amount of change in the objects motion is equal to the Total Force acting on the object divided by the objects mass. ‫ܨ‬௡௘௧
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a is the objects acceleration is the net force acting on the object Fnet m is the objects mass The net force (Fnet) acting on an object can be determined by adding up all the individual forces acting on an object using a free body diagram. Newton’s 3rd Law • For every force, there exists an equal and opposite force. • Forces always occur in action/reaction pairs Examples 1. A book sitting on a table: the book exerts a force on the table; the table exerts an equal and opposite force on the book. 2. A person pushing against a wall: the person exerts a force on the wall; the wall exerts an equal and opposite force on the person. 3. A fish swimming in the water: the fish exerts a force on the water; the water exerts a force on the fish.