Newton’s First Law of Motion1233333.pptx
- 1. ewton’s First Law of Motion Law of Inertia: Resistance to Change
- 2. aw of Inertia: Resistance of Change •From Galileo's initial idea, Isaac Newton developed the concept of inertia and made it his first law of motion. When objects tend to oppose the changes imposed to it, inertia is at play.
- 3. aw of Inertia: Resistance of Change •The law of inertia states that an object at rest remains at rest and an object in constant motion remains to be in that state of motion unless acted upon by an external force.
- 4. aw of Inertia: Resistance of Change •It means that an object continues to be at rest if it was at rest and moving if it was moving if no unbalanced forces are acting on it. The property of objects when it opposes changes in motion is called inertia.
- 5. onsider the following situations in which the net force acting on the object is zero. 1. If an object is not moving, its speed and direction are zero. It means that all forces acting on it are balanced; hence, net force becomes zero.
- 6. 2. An object that is moving at constant velocity has the same speed and is heading in the same direction; therefore, acceleration is zero. This also means that the forces acting on this object are balanced; therefore, the net force is zero.
- 7. v=0 V is not zero
- 8. •In the law of inertia, objects do not accelerate on their own; instead, a net external force has to be imposed on them to oppose the tendency of resistance so that the objects will accelerate.
- 9. Mass As a Measure of Inertia •Inertia is a property that is possessed by any material so long as it has mass. The more massive the object is, the more inertia there is. If an object has great mass, it has a great tendency to resist the changes imposed to it.
- 10. •One example is comparing a truck and a car that are moving at the same velocity. If these vehicles either change their speed or direction, you will see that the truck exhibits more inertia in the effort expended to change its speed and/or direction. It is hard to speed up or slow down a more massive object.
- 11. •Mass and weight are commonly interchangeable quantities. However, they are different in so many aspects. Mass is the amount of matter an object contains. The composition of the material and the associated amount of this composition defines the quantity of mass an object has.
- 12. Weight is the force acting on the matter when acted upon by the force of gravity.
- 13. •On Earth, mass and weight are directly proportional to each other. If the mass is high, its weight is also big. If the mass is halved, the weight is also halved. However, this does not mean that the two are the same.
- 14. •Mass is the fundamental quantity that measures the amount of matter. When the gravitational pull of Earth, for instance, acts on the object that has mass, then the combined quantity is called weight. Weight is the product of mass and acceleration due to gravity.
- 16. •The common unit used for measurement of the amount of matters is kilograms. Acceleration that is because of gravity at sea level has a value and a unit of 9.8 m/s². When the two quantities are multiplied, the combined unit become kg m/s² or collectively known as a NEWTON (N) unit.
- 17. The following table summarizes this. SI Unit of Weight Mass Earth’s Gravity Kilogram meter/second² (kg m/s²) or NEWTON (N) Kilogram (kg) 9.8 meter/second² (kg m/s²)
- 18. • If the pull of gravity changes, its weight also changes, but the mass of the same object does not. Example, the gravity on the moon is only 1/6 as strong as on earth. If a person has a mas of 50 kg, how much will he weigh on earth and the moon? Will mass of the person change when it goes to the moon? On Earth: Mass= 50 kg Gravity on Earth= 9.8 m/s² Weight on Earth= mass x gravity = 50kg x 9.8 m/s² Weight on Earth = 490 kg m/s² or Newton (N) On moon: Mass= 50 kg Gravity on moon= 1/6 (9.8 m/s²) =1.63 m/s² Weight on moon = mass x gravity = 50kg x 1.63 m/s² Weight on moon= 81.67 kg m/s² or Newton (N)