Naeem Swinton
Physics
Mrs. Lawrence
13 May 2013
Physics is
all around us. It pops up daily and we don’t even realize it. I am going to
give 10 examples, simple and detailed, about how Physics is an inevitable
factor we daily fail to recognize.
11. You
know how in movies, or in real life, when someone is on the hood of a car and
then is shot off. The reason for this is newton’s first law, which states,
every object continues in a state of rest or of uniform speed in a straight
line unless acted on by a nonzero net force. Well at first both the car and the
man is at rest. When the car moves, the man does also. They are no in uniform
speed. When the car steps on the brakes, the man wants to continue in his
uniform state, which sends him flying off the car.
22. People
drive everywhere. We drive to work, school, the Bahamas, you name it. In the
car there is a speedometer. The speedometer measures speed, but can also
measure acceleration, which is how quickly velocity changes. Velocity and
acceleration are both Physics topics that we learned about this year.
Acceleration is measured by the change in velocity/ time interval. For example
if a car went from 0 to 60 in 3 seconds the equation would be set up like this.
Acceleration= 60km/h/ 3s= 20km/hs (hour second)
33. One
major activity that incorporates Physics is Skydiving. Skydiving incorporates
gravity, air resistance, free fall, and other physics concepts. Gravity pulls
the person towards the ground. Air resistance is pushing the person in the
opposite direction. The more speed the
person gets the more air resistance is increased. Eventually upward force of
air=downward force of gravity. At this point speed remains constant (terminal
velocity). The net force is 0, therefore acceleration is 0. In order to slow
down the upward force of air must be greater than the downward force of
gravity. One way to increase this is to increase surface area. Parachutes
increase surface area, which increases air resistance. When this happens the
skydiver slows down and safely lands on the ground.
44. In
the army planes are required to drop off medical supply kits. The planes are
usually moving pretty fast and due to that they need to account for their speed
and the distance from the ground. If they are moving at 250mph, then whatever
they drop will move at that same speed because horizontal velocity is constant,
meaning it does not change. The vertical velocity increases due to the force of
gravity. The horizontal and vertical components are completely independent. For
example, if the package is dropped from a hovering helicopter or a moving plane
the packages will land at the same time because of gravity.
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55.
Merry Go Rounds are great for childhood
memories. What you might not know is physics is involved in this part of your
childhood as well. Tangential speed is a huge factor. Tangential speed=
distance covered/time. This means that the person at the farthest side, or to
the outside of the merry go round, will move the fastest. Just think about it
someone on the inside moves slow because they are closer to the axis, which
takes a longer time to do a full rotation. While someone on the outside has to
keep up with someone on the inside they have to cover a larger distance in that
same amount of time and the only way they can do that is if they go faster.(LINK
VIDEO)
66.
As I said earlier, everyone drives. What you
might not have realized while driving is that there are metal lines in the
concrete in front of stoplights. This is physics. The metal lines you see are
what cause electromagnetic induction.
When a loop of wire in a complete circuit, you insert a magnet through
or around the loop of wire and that changes the magnetic field of the loop. In
our cause the metal lines on the ground are the loop of wire and the car is the
magnet. When the car moves over the loop of wire it change the magnetic field
of the loop. This change induces a current, which acts as a signal. This signal
is sent to the box on the street, which is then sent to the light, letting it
know that a car is waiting to go past.
77.
Credit cards are another example of
electromagnetic induction. In the credit card machine, there is a loop of wire.
When the card, which has a strip of containing a series of magnets, moves
through the wire, it changes the magnetic field of the loop. This change
induces a current and this current acts as a signal. This signal tells the
computer what your specific credit card number is.
88.
Do you know how plastic wrap sticks to a plastic
bowl but not metal? This is simple. Plastic wrap is charged by friction and
when brought near the bowl the charges on the bowl polarize. The positive
charges in the bowl move close to the negative charges in the plastic wrap and
the negative charges move away from this plastic wrap. This is because like
charges repel and opposite charges attract. The distance between the opposite
attractive charges is smaller than the distance between the like repelling
charges. The force between the charges is equal to: F= Kq1q2/d2.
Since there is a greater distance between the repulsive forces the force
between them will be less than the closer attractive forces. This is why the
plastic wrap sticks to the bowl. Also metals are insulators and that is why
plastic wrap will not stick to them.
99.
Do you ever wonder what those boxes on your
computer charger are? They are transformers. A transformer basically saves your
computer from damage. Your computer cannot handle the full 120V from the
socket. The transformer takes in that 120V and transforms it into a lower
voltage that your computer can handle. The transformer contains two coils of
wire. The primary and secondary coils. The power is the same in both the coils.
More loops equals more voltage and less loops is less voltage. AC current runs
though the primary coil. This causes the magnetic field of the primary to
change. This changes the magnetic field of the secondary at the same rate. If
the secondary has more loops, and its magnetic field is constantly changing, it
will produce more voltage then the primary. This is a step up transformer. If
the secondary has fewer loops, which your computer plug will have, it will
produce less voltage then the primary. This is a step down transformer.
110.
We are all tough guys out here. Did you ever
push someone really hard then you feel yourself go backwards as well. This is
due to Newton’s third law, which states, whenever one object exerts a force on
a second object, the second object exerts an equal and opposite force on the
first. So basically by you pushing someone, his or her body automatically
pushes you as well. Another funny example is when someone runs at you with a
huge ball. They are putting himself in danger because not only will they send
you flying, but according to newton’s third law, they will also go flying
because if they exert a force that person will uncontrollably exert a force
back.
