Download Reading guide, 2-3 - OPFI Conceptual Physics

Ch2 Physics in Action!!!
2*3 Newton’s Second Law of Motion
Quantitative and Qualitative Observations (p159)
An observation is _____________________ that you get through your ____________.
When you describe __________________of objects, ___________________________
_____________________________________________________________________
____________________________________. For example: _____________________
____________________________________________________________________.
Observations are __________________ if they are based on measurements or ________
__________, because they deal with quantities. For example: ____________________
____________________________________________________________________ .
EVIDENCE FOR NEWTON’S SECOND LAW OF MOTION: (P. 160)
In the investigate, you discovered that is was difficult to push an object with ___________
___________________, because the object would move _________________________.
Therefore, we can conclude that ____________________________________________;
This is a very important observation in physics.
You also found that if you push on ___________________________________________
____________________________________________________________________
____________________________________________________________________.
From this observation, we can conclude that ____________________________________
_____________________________________________________________________
____________________________________________________________________.
Base on these observations (or at least ones very similar to them) Isaac Newton wrote his
____________________________________________. This law states that _______
_____________________________________________________________________
____________________________________________________________________.
The direction of the acceleration is the same as the unbalanced force.
There was evidence of Newton’s 2nd law in the investigate. When you push an object with a
small force, _________________________________________________________.
The speed of the object DID increase, but not very _____________________; BUT when
you pushed the same object with a LARGE force, ________________________________
Newton’s second law states
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_________ in other words, it’s a math way of saying _____________________________
_____________________________________________________________________
_____________________________________________________________________
_______________________ . This relationship is known as a ________________
proportion. In this Investigate, the force was a push. You also found that the same force
on a small mass produced a larger acceleration than it did on a large mass. Newton’s second
law states this, “_____________________________________________________
_____________________________________________________________________
___________________________________________________________________”.
In other words, it’s a math way of saying, ____________________________________
___________________________________________________________________.
We call this relationship an _____________________ proportion—which means to achieve
a big acceleration, you need to apply a large force to a small mass.
AN EQUATION FOR NEWTON’S SECOND LAW OF MOTION (pg. 161)
Newton’s second law of motion can be written as an equation:
𝑎𝑐𝑐𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 =
also, it can be written with symbols 𝑎 =
Where acceleration (a) is expressed in unites of _________________, Force (F) is
expressed in units of ________________, and mass is expressed in units of __________.
We can rewrite the formula for Force, F= ___________________ and we can also rewrite
it for mass, m= __________________________.
NEWTON: A Derived SI unit with a special name (pg 161)
Speed, measure in ____________________, and Acceleration, measured in __________
are both derived units. A derived unit is ______________________________________
____________________________________________________________________.
In the equation for Newton’s 2nd law, Force is expressed as a _____________. But what is
a Newton? A Newton is ___________________________________________________
___________________________________________________. A newton is the force
required to make ______________ of mass accelerate at ________________________.
With this definition, the unit for a newton can be written in its equivalent form:
________________. So to make it simple, __________=1kg*1m/s2 . This form is
important to know when doing calculations to find ________________________________
____________________________________________________________________ .
WHERE THERES ACCELERATION, THERE MUST BE AN UNBALANCED FORCE (PG
162)
There are a lot of everyday forces, some examples include (write 5) _________________
____________________________________________________________________
____________________________________________________________________ .
We find in Newton’s 2nd law that accelerations are _______________________________
____________________________________________________________________.
It does not matter where the force came from. If you see an acceleration, then ________
____________________________________________________________________.
When you apply a force to an object with a small mass, we expect a __________________,
but if you were apply that same exact force to a lager mass, then ___________________.
If you apply that SAME force to a mass that is really, really , really LARGE, then the _____
_____________________________________________________________________
____________________________________________________________________.
Lets apply this to reality. Suppose you pushed a small grocery cart, you would see ________
______________________________________________. But if you applied the same
force to a car, then _____________________________________________________.
Now if you applied the SAME force to a semi-truck, ______________________________
_________________________________________________. So in science, how do we
believe in something we cannot measure? Or does newton’s 2nd law simply stop working when
the mass gets “too big”? in that case, as scientists, we need to figure out how big is too big.
When scientists conduct these experiments, you find that the acceleration __________
_____________________________________________________________________
________. Eventually, the acceleration gets so small it is _________________________
____________________________________________________________________ .
That’s not to say it’s not there, it just means its smaller than your best measurement. In
this way, you can assume that Newton’s 2nd law is ______________________________.
GRAVITY, MASS, WEIGHT, AND NEWTON’S 2ND LAW (PG. 166)
In the investigate, you observed another type of force, ___________________________
__________________________________________. The more coins that were added to
the ruler, the more the ruler ___________________________________________.
Earlier, you noted that when you applied a force with your arm to the ruler, it also caused it to
bend, so….we can conclude that if you observe a ruler bending there must be a force involved.
When you drop a ball, you notice _____________________________________
____________________________________________________________________ .
Newton’s 2nd law tells us that if _____________________________________________
_______________________________________________________________________
__________________________________________________________________.
In both cases, you cannot __________ the force, but you know there is one there, because
________________________________________________.
You know that if you apply a 1 N force to a 1 kg mass, than the resut is a _______________
____________________________________________________________________.
If you drop a 1kg mass on Earth, you can measure the mass accelerating towards the Earth
at a rate of _________________________. This must mean that here is a ___________
____________________________________________________________________.
This is the force of _________________ acting on the mass. You might not be able to see
the force of gravity directly, but you can feel it. The ______________ of an object is the
____________________________________________________________________,
and it depends on ______________________________________________________.
Using Newton’s 2nd law, you can calculate the weight of an object:
F
gravity = ______________________________________, Or,
we way that Weight= _________________.
Where m =_____________________________,
g=_______________________________
w= _______________________________ (by definition)
BALANCED and UNBALANCED FORCES (pg 166)
When one force acts on an object, _________________________. When two forces act on
an object at the same time, the _______________________________ and the _________
_______________________________________determine the motion of the object. If the
forces act in the same direction, ______________________________________________
_______________________________________________________________________.
If the 2 forces are in opposite directions, then the net force _________________________
_______________________________________________________________________.
A free body diagram is _____________________________________________________
if a FBD shows _______________ forces, then the object accelerates, if it shows
__________________forces, it does not, and acts as though there is no force acting on it at
all.