In
this unit I learned about a ton of
physics. Primarily, I learned about inertia, acceleration, and velocity. But I
learned much more than just general definitions and examples. I learned about
every concept into great depth, which has brought me to a better understanding
as to how these concepts relate to everyday life.
I
learned why it feels different to be in a car that is moving with cruise
control on versus when it is speeding up, slowing down, or rounding a curve. If
you’re in a car moving with cruise control, it feels like you’re not moving
whereas if you are in a car that is speeding up, slowing down, or rounding a
curve, you can feel the force being exerted upon the car.
I
learned that if we were in a frictionless environment, then we would never stop
until some sort of force is acted upon us. We would not naturally slow down.
For example, our class performed a lab involving a hovercraft. A hovercraft
does not touch the ground therefore it does not face friction. If when someone
is pushed on a hovercraft, friction is not a force that causes it to stop. The
force that we used to stop our hovercraft when someone was on it was another
person stopping him or her. If the hovercraft had not been stopped by one of
us, it would have continued to move, because according to Newton’s first law of
motion, “Every object continues in a state of rest or uniform speed in a
straight line unless acted on by a nonzero net force.” In other words, an
object will stay at rest until a force is acted upon it and an object will stay
in motion unless a force is acted upon it. In the beginning, the hovercraft was
at rest on the ground of the gym floor with a person on it who was also at rest
and both stayed at rest until the force of the leaf blower caused the
hovercraft to hover above the ground. It stayed at rest above the ground until
someone pushed the hovercraft and once the hovercraft was moving, it would have
continued to do so until someone forced it to stop.
In
Newton’s first law of motion, he mentions net force. Net force is when more
than a single force acts on an object. A force is simply a push or a pull.
Force is measured in newtons. There are multiple types of force such as support
force, gravitational, electrical, magnetic, muscular effort, etc. If there are
multiple forces like these acting on an object it is called net force. Often
examples of net force were used with the pushing and pulling of a box. If two
people were pushing a box with equal force, (both pushing with 50 N), and
another person was pushing the box in the opposite direction with 50 N. The net
force would be 50N. If the net force on a car stopping were backward, you would
lurch forward according to Newton’s first law of motion. Your body and the car
were in forward motion, therefore when the car stops or goes backward, your
body will want to continue in a forward motion.
Another
example that we have seen in this unit, explain the idea of inertia and its
relationship with different forces involved throwing an object into the air. If
an object is thrown up into the air, it will move continue to move upward until
a force is acted upon it, according to Newton’s first law of motion. Here,
there are multiple forces, such a gravitational and the weight of the object
itself. Because there are multiple forces causing this object to come down,
this object has a net force. Another factor that can fall under the category of
force when involving inertia is mass. If a person has a larger mass the force
will need to be stronger to move or stop whereas a person with less mass will
require a smaller force to move or stop it.
The
next two concepts we moved onto after inertia were velocity and acceleration.
Velocity is the speed of an object and its direction of motion. However,
velocity is not the same idea as speed.
Speed describes how fast something moves whereas velocity describes how was
fast and in what direction. Velocity is “directed speed”. For example if a car
were to travel at 60 kilometers per hour, we only know its speed; we do not
know its velocity. However, if we say a car is traveling 60 kilometers per hour
to the north we can specify its velocity. Velocity is changing if either the
speed or the direction is changing, and it is changing if both its speed and
direction are changing. For example, if a car on a curved track has a constant
speed, its velocity will not constant. Its velocity is continuously changing
because the car continues to change direction around the track. This explains
the idea of changing velocity. Constant velocity is means both constant speed
and direction. (Constant speed in other words is steady speed; it does not
speed up or slow down.) Constant direction can only be a straight line. The
path of the object cannot curve. Constant Velocity is motion in a straight line
with a constant speed.
The formulas involving only constant velocity;
(You would usually use the term km/h)
Velocity=Distance/Time
Distance=Velocity x Time
Time= Distance/Velocity
Acceleration
is both the change in velocity and the time it took to change. The key word to
remember when defining acceleration is the word, change. Acceleration
is a rate of a rate. Acceleration applies to both the increases and decreases
in velocity. For example, let’s say there were four images of inclined planes.
The greater the slope of the incline, the greater the acceleration of the ball.
The formulas involving only constant acceleration:
Acceleration=Change in Velocity/Time Interval
Acceleration= Vfinal-Vinitial/Time Interval
If something has constant velocity it
cannot have constant acceleration because constant acceleration means its
getting faster where as constant velocity means it’s staying the same. Constant
acceleration means an object such as the car is covering more ground per time
interval where as constant velocity means the car is going at the exact same
speed. So if the car in the video is going 60 miles per hour its acceleration
is increasing where as its velocity is constant.
Formulas for
Constant Acceleration:
Distance=1/2
Acceleration x Time x Time (how far equation)
Velocity=
Acceleration x Time (how fast) ß usually used whne talking about the
different inclines tested by Galileo.
Formulas for
Constant Velocity:
Velocity=
Distance/ Time (how fast)
Distance=
Velocity/ Time (how far)
Of
course all of this information was a lot to learn and many of the concepts were
very challenging to understand, but I think the both acceleration and velocity
were the most difficult for me. Both of those were main points of this unit so
being confused about acceleration and velocity might seem too broad, but it
really took a lot for me to get the difference between these two correct. I
often got the Change in Velocity over Time confused with the Distance over Time
and got them mixed up between equations. Also, putting the definitions and idea
into real life scenarios would throw me off a lot because I always knew the
reasoning for what was happening or how much time it took for this or that but
when putting that into words I really struggled. Another obstacle that really
challenged me in this unit is just class discussion in general. I knew the
answer in the back of my head for many questions asked in class, however, once
I was supposed to say it out loud, I couldn’t. I soon began to just stop
raising my hand in class because I knew my mind would go blank.
I
overcame my struggle to understand two of the three units main ideas by just reviewing
notes and formulas a lot as well as writing the formulas down and plugging numbers
into them. Also, I think by slowing the problem down a little bit and taking
more time than I was before.
This
unit I definitely had my ups and downs with problem-solving skills and effort.
I have a strong effort mind set but this unit when it came to consistently
being on top of all my homework, all my blog posts, etc; I struggled
significantly. Most of the time I
would think I completed all my homework, but then there would always be
something else I didn’t do. When it came to blog posts, I would usually write
them in study hall and then just forget to post them until after the assignment
would do. Another factor that contributed to the downs in my efforts would
definitely be confidence in physics. A lot of the time, I knew the answer but I
thought I definitely had the wrong answer. Either way I should raise my hand,
because either way I will gain better understanding by participating.
My
goals for next unit are definitely to improve everything I struggled with. To
improve my lagging effort, next unit I will try to complete almost all of my
homework, post all of my blogs on time, and raise my hand more in class. For
the homework situation, I’m going to make a designated time to do my physics
homework and at that time I will look at both the assignment sheet and my
agenda book. To improve posting my blog posts on time, I will always finish the
blog posts at night and as soon as
I’ve finished the blog post I will post it to the group no matter what. Again,
to improve my confidence in physics, I will just raise my hand for any question
I think I have at least a plausible answer.
Here is the link to my podcast on Velocity;
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