Department

Astronomy & AstrophysicsCourse Code

AST101H1Professor

Clifford Orwin chapter 4

Newtons 1st law---An object at rest remains at rest, and an object in motion remains in

motion at constant speed and in a straight line unless acted on by an unbalanced force.

eg. a bike laying on the ground ﬂat stays like that unless an unbalanced force acts on it

( a person lifting the bike up) and a rolling bike will keep rolling and it will only stop

unless an unbalanced force acts on it. The combined friction from ground and air will

cause it to slow down. WITHOUT friction the bike would keep on going forever.

2nd law---The acceleration of an object depends on the mass of the object and the

amount of force applied.

acceleration=force/mass ( the larger the force, the larger the acceleration)

eg. a person pushing a bike with little force with just get the bike rolling

a person pushing a bike with maximum force with make the bike accelerate

!!!!BUT MASS ALSO PLAYS A ROLE

a person pushing a bike with a child riding=bike will move faster

a person pushing a bike with an adult riding=bike moving much slower

THESE BIKE RIDERS ALSO HAVE MOMENTUM

momentum=mass*velocity

NEWTONS 2ND LAW OF MOTION AFFECTS MOMENTUM BECUSE:

since an unbalanced force causes acceleration, which is a change in velocity, then force

also changes momentum

3rd law----Forces act in equal and opposing pairs

you push down on the ground when u walk and the ground pushes up towards your feet

3 basic terms on how an object is moving

1)Speed- how far a car will go in a certain time (100km/hr)

2)Velocity- both speed and time

3)Acceleration- if the speed or direction change (slowing speed or change in direction

is negative acceleration

Galileo- demonstrated that gravity accelerates all objects by the same amount

regardless of their mass

*air resistance causes difference in acceleration*

Acceleration of Gravity- acceleration of falling objects (g)

*Earth acceleration for falling objects is 10m/s*

www.notesolution.com

-An objects momentum is the product of its mass and velocity (momentum=mass*velocity)

-The only way to change momentum is to apply force

Angular momentum- object that is either spinning or moving along a curved path

Torque- force used to change an objects angular momentum (twisting force)

MASS AND WEIGHT

Mass- amount of matter in your body

weight- scale measurements also, depends on body mass and force(gravity) acting on

your mass

example: elevator

when standing in an elevator moving up your mass does not change but your weight

does by becoming heavier and when moving down you become lighter

example: #2

weight less on moon because gravity is weaker

Free-Fall- falling without any resistance to slow you down (consequently makes you

weightless)

-astronauts are in constant free fall

Newton systems of laws that govern all motion

-delivered the ﬁnal blow to Aristotle"s physics

-Newton brought the heavens and earth together as one universe

Newtons laws of motion

1st law- objects remain in motion unless a force acts to stop them (An object at rest

remains at rest, and an object in motion remains in motion at constant speed and in a

straight line unless acted on by an unbalanced force.)

example: a bike laying on the ground ﬂat stays like that unless an unbalanced force acts

on it ( a person lifting the bike up) and a rolling bike will keep rolling and it will only stop

unless an unbalanced force acts on it. The combined friction from ground and air will

cause it to slow down. WITHOUT friction the bike would keep on going forever.

2nd law- he acceleration of an object depends on the mass of the object and the

amount of force applied.

acceleration=force/mass ( the larger the force, the larger the acceleration)

example: a person pushing a bike with little force with just get the bike rolling

a person pushing a bike with maximum force with make the bike accelerate

!!!!BUT MASS ALSO PLAYS A ROLE

www.notesolution.com

a person pushing a bike with a child riding=bike will move faster

a person pushing a bike with an adult riding=bike moving much slower

3rd law-for any force, there is always an equal and opposite reaction force

example: you push down on the ground when u walk and the ground pushes up towards

your feet

www.notesolution.com

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###### Document Summary

But mass also plays a role a person pushing a bike with a child riding=bike will move faster a person pushing a bike with an adult riding=bike moving much slower. Newtons 2nd law of motion affects momentum becuse: since an unbalanced force causes acceleration, which is a change in velocity, then force also changes momentum. 3rd law----forces act in equal and opposing pairs you push down on the ground when u walk and the ground pushes up towards your feet. 3 basic terms on how an object is moving. 1)speed- how far a car will go in a certain time (100km/hr) 3)acceleration- if the speed or direction change (slowing speed or change in direction is negative acceleration. Galileo- demonstrated that gravity accelerates all objects by the same amount regardless of their mass. Acceleration of gravity- acceleration of falling objects (g) *earth acceleration for falling objects is 10m/s* www. notesolution. com. An objects momentum is the product of its mass and velocity (momentum=mass*velocity)

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