21st Law of MotionAn 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.
3ExamplesCan you explain these using the 1st Law of Motion?
41st 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.
5Law of InertiaObjects are lazy – they do not want to stop what they are doing.What can we call this “laziness?”InertiaInertia is a measure of it’s resistance to change.The more resistant, the more inertiaNewtons’ First Law is also called the
62nd Law of Motion Usually stated as an equation: F = ma What does this mean?And don’t say force equals mass times acceleration. Anyone can say that, but do you really understand what it means?What if I restated the equation?
7Newton’s 2nd 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.Let’s look at this relationship.
8Let’s Look Mathematically If I double the numerator, what happens?= = 8When one variable increases, another variable increases the same amount.This is called a direct proportionWhich 2 variables are directly proportional?What does that mean?But this is science class!
9Math and ScienceWhat happens when I increase the denominator?Let’s try!4 = =4 8This is called an indirect proportion, or inverse proportionWhich 2 variables are inversely proportional?What does that mean?
10Newton’s 2nd LawLook at the equation. Think of the previous fractions. Can you explain what it means now?
112nd Law of MotionThe greater the applied force, the faster the object will move (acceleration).The more mass an object has, the more force you need to change it’s motion
123rd Law of MotionFor every action, there is an equal and opposite action.
13Let’s Review Newton Once moving at a steady speed In a straight line It will continue movingAt a steady speedOnce standing stillIt will stay still
14Newton It accelerates in the direction that you push it If you push twice as hard, it accelerates twice as muchIf it has twice the massIt accelerates half as much