Presentation on theme: "Newton’s Laws of Motion No, not the “fig newton” guy. …I don’t think…not sure really… Ok, its possible."— Presentation transcript:
Newton’s Laws of Motion No, not the “fig newton” guy. …I don’t think…not sure really… Ok, its possible.
The British scientist Sir Isaac Newton (1642–1727) was able to state rules that describe the effects of forces on the motion of objects These rules are known as Newton's law's of motion.
The first law of motion: “You do not talk about motion!” Newton's first law of motion states that an object moving at a constant velocity keeps moving at that velocity unless an unbalanced net force acts on it. If an object is at rest, it stays at rest unless an unbalanced net force acts on it. This law is sometimes called the law of inertia.
Why wear a seatbelt? Picture yourself in a car that is moving at 25 mph. –You are not wearing a seatbelt, because you’re “not going very fast”. If the car comes to an immediate stop, as it would during a collision, what will happen to your body? Will it stop with the car?
What happens in a crash. The law of inertia can explain what happens in a car crash. A car traveling 25 mph during a head on collision will stop in about 0.1 seconds.
BAM! Any passenger not wearing a safety belt continues to move forward at the same speed the car was traveling. Within about 0.02 s (1/50 of a second) after the car stops, unbelted passengers slam into the dashboard, steering wheel, windshield, or the backs of the front seats.
Air bags, Crumple zones ect.. Air bags act to increase the time of impact, reducing the acceleration (and reducing the force of your body’s impact). Crumple zones work in the same way: parts of a car are designed to collaspe during an impact, increasing the time it takes to come to a complete stop (they also ‘absorb’ energy)
Newton’s second law: Newton’s second law of motion describes how the forces exerted on an object, its mass, and its acceleration are related. Recall that acceleration is the change in velocity divided by the time it takes for the change to occur. So, a hard-thrown ball has a greater acceleration than a gently thrown ball.
Mass? Which has more force? A big, heavy ball or a little ball? Assuming they are accelerating at the same rate.
Force, mass and acceleration are related! Newton’s second law of motion states that the acceleration of an object is in the same direction as the net force on the object, and that the acceleration can be calculated from the following equation:
Rearrange… Newtons second law can also be used to calculate force… So….