Presentation on theme: "Newtons Laws of Motion. 1 st Law of Motion An object at rest will stay at rest and an object in motion will stay in motion (in the same direction and."— Presentation transcript:
Newtons Laws of Motion
1 st Law of Motion An object at rest will stay at rest and an object in motion will stay in motion (in the same direction and at a constant speed) UNLESS an unbalanced force is applied.
Examples Can you explain these using the 1 st Law of Motion?
1 st Law More simply stated: If they are moving, they want to stay moving. If they are still, they want to stay still. The only way to change what they are doing is to apply a force.
Law of Inertia Objects are lazy – they do not want to stop what they are doing. What can we call this laziness? Inertia Inertia is a measure of its resistance to change. The more resistant, the more inertia Newtons First Law is also called the
2 nd Law of Motion Usually stated as an equation: F = ma What does this mean? And dont say force equals mass times acceleration. Anyone can say that, but do you really understand what it means? What if I restated the equation?
Newtons 2 nd Law Explained It means the acceleration of an object depends on two things – the mass of the object and the amount of force you apply to change its motion. Lets look at this relationship.
Lets Look Mathematically If I double the numerator, what happens? = 4 = When one variable increases, another variable increases the same amount. This is called a direct proportion Which 2 variables are directly proportional? What does that mean? But this is science class!
Math and Science What happens when I increase the denominator? Lets try! 4 = 4 = 48 This is called an indirect proportion, or inverse proportion Which 2 variables are inversely proportional? What does that mean?
Newtons 2 nd Law Look at the equation. Think of the previous fractions. Can you explain what it means now?
2 nd Law of Motion The greater the applied force, the faster the object will move (acceleration). The more mass an object has, the more force you need to change its motion
3 rd Law of Motion For every action, there is an equal and opposite action.
Lets Review Newton Once moving at a steady speed In a straight line It will continue moving At a steady speed In a straight line Once standing still It will stay still
Newton It accelerates in the direction that you push it If you push twice as hard, it accelerates twice as much If it has twice the mass It accelerates half as much
Newton If you push on it It pushes on you
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