Newton's Three Laws of Motion 4 January 1643 – 31 March 1727

Newton's First Law of Motion An object at rest tends to stay at rest. An object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force Inertia: The tendency of an object to keep moving at the same speed and in the same direction

Newton's First Law of Motion Examples Car sudden acceleration The drink , which was at rest, wants to stay at rest. Possible result : spill

Newton's First Law of Motion Examples Car going 35 miles/hr. Driver also going 35 miles/hr ( but he does not feel it : they are not moving relative to the car ). Brisk stop of the car => the driver keeps traveling 35 miles/hr until acted on by an external force : steering wheel, dashboard, windshield. Hence the importance of the Driver Seat Belt

Newton's First Law of Motion Examples Head resists the motion and moves to the back rear-end collisions Hence the importance of the Driver Headrest

Newton's First Law of Motion More Examples

Newton's Third Law of Motion For every action there is an equal and opposite re-action. Democrats Republicans

Newton's Third Law of Motion

Newton's Third Law of Motion Rockets work by pushing exhaust gases out Opposite force pushing the rocket upward Thrust force pushing downward Skateboard example

Newton's Second Law of Motion F = m.a Or a = F/m F force: the push or pull on an object that in some way affects its motion m mass: the amount of matter an object has a acceleration W Weight: the force which pulls you toward the center of the Earth (or any other body)

Newton's Second Law of Motion Units: [F] = [M] [a] [F] = kg m/s2 1 Newton (N)  1 kg m/s2

Newton's Second Law of Motion the harder you hit a baseball, the faster the ball goes a = F/m. If you substitute the baseball with a more massive ball , ( increasing m ), it will no go far. It will take the 18 wheels truck longer time to come to stop than the smaller truck …due to their mass differences.

Newton's Second Law of Motion If Then No Acceleration  * Object at rest tends to stay at rest * object in motion tends to stay in motion with the same speed and in the same direction Newton’s First Law

Newton's Second Law of Motion Acceleration Due to Gravity                                      Gravitational force (weight) is proportional to mass. Double the mass and the gravitational force will be doubled also. Ratio of weight to mass is always the same:  g This is explained further, below. Figure Source : http://sol.sci.uop.edu/~jfalward/physics17/chapter2/chapter2.html