1.04k likes | 1.3k Views
Newton’s laws. NEWTON HIMSELF. Newton. Newton. Life. Scholar Brilliant mind Became Head of Oxford Colleges in England Royal Society of England Master everything in his age Teacher Help to develop whole branch of Mathematics Newtonian physics Alchemist. LIMITATIONS OF HIS LAWS.
E N D
Life Scholar Brilliant mind Became Head of Oxford Colleges in England Royal Society of England Master everything in his age Teacher Help to develop whole branch of Mathematics Newtonian physics Alchemist
Newton’s laws of motion Clearly laid down the rules that govern why things move in our world Rules can not fully explain motion on or smaller than the atomic level or movement close to the speed of light
Review Net force Balanced Force Unbalanced forces
NEWTON’S FIRST LAW Law of Inertia
A bowling ball will move with nearly constant velocity No significant friction from the ground or air resistance to help change the bowling ball’s motion Velocity of ball changes only when it hits the pins or the back wall of lane
Newton’s first law An object at rest stays at rest or an object in motion stays in motion UNLESS acted upon by a net outside force
How does the 1st law relate to you as you walk down the hall?
Newton’s first law Definition
Why should a baby not be transported on a car in a person’s lap? Would it be ok if you put the seat belt around you and the baby?
If Fluffy the Kitty was sleeping (without a seatbelt) in the rear window well of a sedan… Describe Fluffy’s motion if the car was involved in a head-on collision?
How does one get whiplash? How does whiplash relate to 1st law?
1st law of motion An object at ______, stays at ______ An object in motion, stays at a _______ rate Unless A net outside ________ acts upon it.
NEWTON’S SECOND LAW The equation law
Newton’s 2nd law If there is a net force on an object, then the object will accelerate The amount of acceleration depends on the following relationship: A = Fnet m
2nd law A = Fnet / m or rearranged Fnet = ma Triangle set up to solve for different variables Units: acc m/s2 Fnet N mass kg
2nd law can be represented using a triangle Fnet = m a Fnet M A t
When Solving problems using 2nd law Fnet means net force or the sum of all forces on the object Force is measured in N (Newtons) Mass is measured in kg Acceleration is measured in m/s2
The greater amount of net force applied, the larger the acceleration of a specific object
The greater the mass, more force is needed to produce the same acceleration
An object will accelerate at a higher rate as more force is applied An object will accelerate if moremass is added to it
2nd law An object will change its motion only if a net force is applied to it (fnet ≠ 0)
If you apply the same force to roll each a long the floor, how will their motion compare?
3rd Law For every _____________ There is an __________ but opposite __________.
Newton’s Third Law For every action force, there is an equal reaction force applies in the opposite direction
What are Action-Reaction forces For any force applied to an object, the object will respond with a like force back Forces are equal in size Forces that are applied to different objects Examples in Picture?
Action and Reaction Forces Action Force: the force of most interest, initiates the action Reaction force: force applies in response to action force
Action and reaction forces Equal and opposite Applied to different objects Applied at same time May have different effects
If all forces are equal and opposite, how does anything move?
Answer Though equal in size, the forces act on different objects Force of box on ground Force of ground on box
The effect of the action reaction forces may differ on an object. By first law, objects accelerate if there is a net force on them What other piece of information is required to determine the amount of acceleration?
Consider the guys hands pressing down on desk. What are the action /reaction forces?
Determining the weight of an object • Weight = force due to gravity • F = ma (by 2nd law) • F = mass (in Kg) times (-9.8) • Determine mass by measurement on scale or conversion
Determining mass • Convert from pounds to kg by: =(weight in lbs) / 2.2