# Danny's Blog

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## Archery

we are starting the archery unit in gym and I was wondering what the physics we behind it. I did some research and I found some pretty cool stuff about it, I found that when aiming archers generally aim to one side of their target and the arrow straightens out during flight. the arrow is able to straighten out because the fishtail at the end of the arrow oscillates causing the arrow to move back towards the center.

## Skydiving

I was watching television the other day and I saw a commercial of someone skydiving, this got me thinking that there has to be physics behind it. I learned that the physics of skydiving involves the interaction between gravity and air resistance. a skydiver keeps accelerating downward until he or she reaches terminal speed, the speed at which the air resistance on the skydiver equals the force of gravity acting on him or her.

## Frisbee

I was at the park the other day and saw a few people plying Frisbee, and this got me thinking, just how does a Frisbee fly? I learned that once in the air the Frisbee's unique shapes allows to gain lift and angular momentum allowing it to stay in flight. I also learned that Newton's third law plays a vital role in a Frisbee's flight. the Frisbee forces air down and in turn the air forces the Frisbee upward.

## Harmonics

we have been talking about sound waves a lot in class recently and how they are found in music. I did some research of my own and they really are. I learned how guitar strings have a specific frequency in which they will naturally vibrate and are known as harmonics. I learned that if a guitar only had a single frequency it would make only one sound but because it has so many harmonics present it is able to produce different pitches and thus different sounds

## Breaking glass

in class we recently watch a Mythbusters in which they tested whether or not a human can shatter a glass with their voice. to my surprise they were successful, this sparked my curiosity for the topic. from looking into it I found that the singer wasw able to break the glass unassisted with a combination of matching the glasses natural frequency and by using the right level of amplitude for his own. I found that by enacting these two variables onto the glass the effect would be resonance. the sin

## Elevators

seeing as how I always struggle with elevator problems so I decided to do an entry on them to help with my understanding of them. when accelerating upward in an elevator, a persons inertia wants to stay put so it results in a greater force between the scale and the person. because of this the normal force is larger and the weight is larger. when accelerating downward in an elevator, a persons inertia still wants to remain put so it results in a lesser force between the scale and the person. th

## walkin

you walk everyday, and yet do you ever stop and think about what actually is going on while you're walking? if it weren't for the friction between your feet and the ground propelling you forward you wouldn't be able to go anywhere. Furthermore Newton's third law is greatly involved in the act of walking. Every step you take is responded by an opposite force coming from the ground, propelling you forward and giving you speed. this is why when you run you have to apply much more force to the groun

## catapults.

Through the many trials of creating our catapult, my teammates and I were able to discover the physics that went along with it. we learned that a catapult is able to launch its projectile through either three different stored energy mechanisms; tension, gravity, or torsion. we inevitably used gravity because we thought that it would be the most effective. we used a plastic crate full of bricks as our source of energy to launch the softball. But even though all the bricks greatly outweighed the

## soccer

in many ways physics has a lot to do with soccer. for instance, when cutting while running takes a lot of force. Newton's first and third law of motion apply to this action. Newton's first law is applicable here because you continue moving in that direction until you exert a force(your plant leg) to change it. The third law works here because the force your foot is inflicting on the ground is counteracted with the same force but in the opposite direction by the ground itself.

## sleeping

one of my favorite things in the world is sleeping, I'd take sleep over physics homework any day of the week. But I will admit physics is greatly involved in the act of sleep. For instance, while laying on your bed you create an example of Newton's third law of motion: for every action there is an equal and opposite reaction. The first action/force would be you laying on the bed, pushing it downward. The second action/force would be the bed pushing back at you with the same amount of force but i

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