1 G8 Science Q1- Week 1- Newton_s Law of Motion.pptx

Science 8 explain the three Laws of motion

1. NEWTON’S LAWS OF MOTION PREPARED BY : TYPE YOUR NAME HERE

2. S8FE-Ia-15 Investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion

3. Early Ideas on FORCE & MOTION Aristotle Believed that a continuous application of force on a body is required to produce and maintain the motion of the body The absence of an external force, a moving body will stop

4. Once you stop pulling the chair, it will stay at rest .

5. Objects continue to move though the force that started the motion of the body is removed

6. Galileo He disproved the theories made by Aristotle He made an experiments on an inclined plane & through logical thinking

7. h A E D C Ball rolling down and up inclined planes

8. Galileo said that the smaller the inclination of the plane in relation to the horizontal, the farther the ball will have to roll to reach the same height. He concluded that the smaller the angle of inclination from the horizontal the less is the deceleration of the ball. He reasoned that if that is the case, the deceleration becomes zero when the angle of inclination is zero.

9. Galileo with his logical mind concluded that a moving body along a horizontal frictionless surface does not require a continuous application of force to maintain its uniform velocity.

10. ISAAC NEWTON Sir Isaac Newton was one of the greatest scientists and mathematicians that ever lived. He was born in England on December 25, 1643. He was born the same year that Galileo died. He lived for 85 years.

11. He was interested in experimental science thus his studies restated the idea of Galileo and came up with the Law of Inertia

12. First Law : LAW OF INERTIA INERTIA - A property of a body to resist changes in its motion It is equal to the mass of the body

13. LAW OF INERTIA An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

14. What does this mean? This means that there is a natural tendency of objects to keep on doing what they're doing. All objects resist changes in their state of motion. In the absence of an unbalanced force, an object in motion will maintain this state of motion.

15. This law is the same reason why you should always wear your seatbelt.                                                                                  

16. Second Law: LAW OF ACCELERATION Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

17. What does this mean? Everyone unconsciously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.

18. However, the Second Law gives us an exact relationship between force, mass, and acceleration. It can be expressed as a mathematical equation:

19. example of how Newton's Second Law works

20. Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car go 0.05 m/s/s. Using Newton's Second Law, you can compute how much force Mike is applying to the car.

21. Newtons 3rd Law of Motion LAW OF ACTION AND REACTION For every action there is an equal and opposite reaction.

22. What does this mean? This means that for every force there is a reaction force that is equal in size, but opposite in direction. That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard.

23. Let's study how a rocket works to understand Newton's Third Law. The rocket's action is to push down on the ground with the force of its powerful engines, and the reaction is that the ground pushes the rocket upwards with an equal force.

24. The rocket is pushing the ground Pushes the rocket upward by the ground with equal force

25. PRACTICE TEST  The tendency of an object to resist change in its motion is known as a. Mass b. Inertia c. Force d. Motion   A net force (an unbalanced force that changes motion) causes an object to a. stay at the same speed. b. not move. c. Accelerate or decelerate d. None of these   Forces that are equal in magnitude and opposite in direction are known as a. balanced forces b. net forces c. friction forces d. None of these

26. Two boys wearing in-line skates are standing on a smooth surface with the palms of their hands touching and their arms bent, as shown above. If Boy X pushes by straightening his arms out while Boy Y holds his arms in the original position, what is the motion of the two boys?   a. Boy X does not move and Boy Y moves backward. b. Boy Y does not move and Boy X moves backward. c. Boy X and Boy Y both move backward. The motion depends on how hard Boy X pushes. d. Both will not move.

27. In science, a push or a pull of an object is called a(n) a. force. b. acceleration. c. inertia. d. friction   You are riding fast on a skateboard when your wheel suddenly gets stuck in a crack on the sidewalk. Why does your body go flying forward? a. there is a net force pushing you off your skateboard b. your inertia keeps you moving forward c. someone pushed you d. none of these

28. The force that pulls falling objects toward Earth is called a. Gravity b. Free fall c. Inertia d. Acceleration   According to Newton’s third law of motion, when a hammer strikes and exerts force on a nail, the nail a. creates a friction with the hammer. b. disappears into the wood. c. exerts an equal force back on the hammer. d. Nothing will happen

29. “However difficult life may seem, there is  always something you can do  and succeed at.” ―  STEPHEN HAWKING