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Newton’s Laws

Newton’s Laws. Isaac Newton (1642 – 1727). The Father of Force. What is a Force?. Force can be defined as a push or a pull. Or anything else that has the ability to change motion. Force:. kilogram x m/sec 2. kg x m/s 2. newton. Easier than saying kilogram  m/sec 2. N.

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Newton’s Laws

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  1. Newton’s Laws Isaac Newton (1642 – 1727) The Father of Force

  2. What is a Force? Force can be defined as a push or a pull. Or anything else that has the ability to change motion

  3. Force: kilogram x m/sec2 kg x m/s2 newton Easier than saying kilogram  m/sec2 N Is even easier!

  4. 2 Kg Mass To Understand Force… You must understand the difference between Mass Weight AND

  5. What is Mass? The amount of “stuff” in an object. 1 Kg Mass 1.5 Kg Mass 2 Kg Mass Mass is measured in Kilograms

  6. How is Mass Different Than Weight? Weight is measurement of FORCE. 2.2 pounds 4.4 pounds 3.3 pounds 9.8 N 19.7 N 14.8 N (1 kg x 9.86 m/s2) (2 kg x 9.86 m/s2) (1.5 kg x 9.8 6m/s2) force due to gravity (9.8 m/s2) force due to gravity(9.8 m/s2) force due to gravity (9.8 m/s2) 1.0 Kg Mass 1.5 Kg Mass 2.0 Kg Mass DON’T USEkilograms (kg) as a measurement for weight (force) USE pounds (lb) or N for force.

  7. Different Gravity? Mass is the Same:1 kgBut the WEIGHT… 1 Kg Mass 2.2 Pounds 7 On the moon1.0 kgwould weigh 0.3 lbs On the sun1.0 kgwould weigh 59.5 lbs On Mars1.0 kgwould weigh 0.8 lbs What’s “Your Weight On Other Worlds?” http://www.exploratorium.edu/ronh/weight/

  8. Newton's Three Laws of Motion These laws explain why objects move (or don't move). Let’s look at Newton's three laws of motion...

  9. Newton's 3 Laws An object will remain at rest unless acted upon by an “unbalanced” force. An object in motion will continue with constant speed and direction, unless acted on by an unbalanced force. 1 This law shows how force, mass and acceleration are related as shown in the equation below: Force = mass x acceleration 2 For every action there is an equal and opposite reaction 3

  10. Newton’s First Law: Balanced Forces An object will maintain a constant state of motion (balanced). This means an object at rest tends to stay at rest and an object in motion tends to stay in motion Forces that are balanced can be: This is known as Not in motion In Motion Inertia Stay in motion: a bowling ball tossed in space Stay at rest: a book on a table It will go on and on forever Table pushes up on book IP&C Gravity pulls down on book

  11. Newton’s First Law: Unbalanced Forces An unbalanced force is a force that changes the motion. In space there is no resistance to cause friction, so a bowling ball would stay in motion ...unless another object got in the way… The book below slides and then stops because resistant force called friction. Friction is force that opposes motion. It kind of reminds of a few movies I’ve seen lately... Force of friction stops the book IP&C

  12. Of course “frictional” force happens on earth... But, if you weren’t wearing a safety belt You would continue your motion… Don’t let this happen to you, buckle up!

  13. Newton’s Second Law: Force = Mass X Acceleration Force and acceleration are related You are going down the road on your inline skates. Suddenly you look to your right and see a car accelerating faster coming right for YOU! You look for an escape to your left… Oh no! There’s a rock at the edge of neatly manicured lawn. Which will you choose... A massive car accelerating faster? ...or a medium size rock not in motion? Force (car) = mass x acceleration is greater than Force (rock) = mass x acceleration You still might get hurt, but would be much worse off choosing the force of the car over the force of the rock. Good Choice

  14. Solving Force Problems Step 1 Read the problem and write down the formula you will use. Step 2 Plug in the information you know into the formula. Step 3 Solve the math. Step 4 Write down the answer with the correct units.

  15. Consider the problem… “How much force is needed to accelerate a 1400-kg car 2 m/s2? ” Step 1 Read the problem, draw a picture 1400-kgcar How much force? 2 m/s2 Formula Plug-in Answer F = m = a = Units, units, units!

  16. “How much force is needed to accelerate a 1400-kg car 2 m/s2? ” Step 2 Write down what you know, What are you trying to find? 1400-kgcar 2 m/s2 Formula Plug-in Answer ? F = 1400 kg m = 2 m/s2 a = Units, units, units!

  17. “How much force is needed to accelerate a 1400-kg car 2 m/s2? ” Step 3 Set up the formula, F = m x a Formula Plug-in Answer ? F = 1400 kg m = m x a 2 m/s2 a = Units, units, units!

  18. “How much force is needed to accelerate a 1400-kg car 2 m/s2? ” Step 4 Plug in the numbers Solve 2800 kg x m/s2 Formula Plug-in Answer ? F = 1400 kg m = m x a 2800 kg x m/s2 1400 kg x 2 m/s2 2 m/s2 a = Units, units, units!

  19. Be sure to do the problems: • Helpful Hints: a = F / m F = m x a m = F / a

  20. The unit for force: newton 1 kg x m/s2 = 1 newton or 1N Which one would you rather write for your answer? 2800 N …I thought so.

  21. Newton’s Third Law: Action / Reaction For every action there is an equal and opposite reaction Look at the picture below: What is the action? What is the reaction? As the gases push downward out of the rocket, The the rocket is pushed upward by the gases

  22. Newton's 3 Laws An object will remain at rest unless acted upon by an “unbalanced” force. An object in motion will continue with constant speed and direction, unless acted on by an unbalanced force. 1 This law shows how force, mass and acceleration are related as shown in the equation below: Force = mass x acceleration 2 For every action there is an equal and opposite reaction 3

  23. Newton’s Laws explain how Earthquakes create such devastation Most of the time the Earth’s massive plates push on each to move very slowly. But, sometimes a massive plate exerts a greater amount of force that accelerate another plate. This results in an earthquake. To learn more go to: http://vcourseware5.calstatela.edu/VirtualEarthquake/VQuakeIntro.html

  24. The Story of Newton’s Apple Newton sat under an apple tree and an apple fell on his head. That falling apple gave him a revelation. And led him to describe a force called... GRAVITY. But DON’T think of gravity as falling… It is the pull(force) that an object has on another.

  25. Newton’s apple was falling because the massive gravitational force of the Earth was pulling the apple towards Earth...

  26. Gravity is the force that ALL objects in the UNIVERSE exert on each other... Newton said that gravitational force depends on 2 things: The DISTANCE of the objects The MASS of the objects LESS gravitational force compared to... The blue object has more gravitational force than the green object because the blue object has more MASS. MORE gravitation force here.

  27. Newton’s apple fell because the Earth’s pull of gravity.... The itty-bitty pull of apple is too small to pull the Earth, so it is pulled to the Earth... was more massive than the apple’spull of gravity on the Earth

  28. The moon is a satellite too.. The pull of gravity keeps satellites orbiting around the Earth

  29. Satellites are sent away and placed in the exact spot where the Earth’s gravity pulls them into a “continuous free fall” or orbit... The moon does the same thing. The Earth is round and the satellite continues to “just miss” entering into the Earth’s atmosphere.

  30. Does the moon’s gravitational pull effect the Earth? Yes, the moon’s gravity is large enough to actually pull water out of the ocean from space… Well, not quite that much...just enough to create motion of the tides.

  31. Newton is even credited with inventing CALCULUS. Needless to say, Newton was very important in shaping our understanding of science

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