Physics in Real Life

1) Category: Natural

Title: Dribble Dribble

Physics Concept: Action/Reaction

Description of Photo: In this photo, my brother is dribbling a basketball similar to how one would do so when he or she is playing basketball. When my brother dribbles the ball, he hits the ball towards the ground repeatedly as a way of moving the ball.

Explanation of Physics: Since the ball is made of rubber, if he bounces the ball on the ground with a strong force, the ball will come up with a strong force as well. There are many ways for a player to control his or her dribbling to make sure that the ball does not move too far out of reach. First, he or she can bounce the ball at a force that keeps the ball at waist height. This ideology corresponds well with Newton's third law of an action with an equal and opposite reaction. My brother exerts an applied force on the ball. In contrast, when the ball hits the ground, the normal force of the ground exerts itself on the ball. This action and subsequent reaction, causes the ball to bounce.

2) Category: Contrived

Title: Parachuting His Way to Victory

Physics Concept: Freefall/Projectile Motion

Description of Photo: In this photo, I tied a small parachute that I found in my house and tied it to one of my old action figures. I did this in order to show the effects of freefall motion since I could not go skydiving.

Explanation of Physics: The physics in this photo is almost synonymous with the subjects of freefall and projectile motion. In freefall, an object falls to the earth with an acceleration of -9.8 m/s^2. Since the action figure has a parachute attached to it, it reaches the earth much slower than if it had no parachute. However, one can still learn the effects that a parachute has on the rate at which an object falls to the earth. In addition, this photo can shed light on the subject of projectile motion. A projectile is an object thrown into space by the exertion of force. Due to the fact that the action figure was dropped, it is indeed a projectile. 

3) Category: Contrived

Title: No Lift, Just Drag

Physics Concept: Friction

Description of the Photo: In this photo, my brother attempts to drag this chair across the room. He knows that it is heavy, so he has to figure out some mechanism to do it effectively.

Explanation of Physics: When my brother drags the chair across the floor, he knows that he wants as little friction as possible to make the drag easy. In other words, he wants a low friction coefficient so that he does not have to exert a lot of force on the chair. He is already at a disadvantage because the carpet has a higher friction coefficient than the carpet. Therefore in order to decrease the friction, he tilts the chair so that only two of the legs touch the floor instead of four. Also, it is very hard to first start moving the chair due to the high static friction which comes with making the chair move. After, the kinetic friction will be much less than the static friction allowing easy movement. In order for the chair to move, my brother must exert a stronger applied force to move the chair to overcome the kinetic friction. 

4) Category: Contrived

Title: Flying High, The Limit is The Sky

Physics Concept: Center of Mass

Description of Photo: In this photo, my friend Darius is attempting to jump over a bar in high jump that is 6 feet 11 inches in the air. He was successful!

Explanation of Physics: I, a fellow high jumper, know that there is a significant amount of physics involved in the high jump most of all. First, for Darius to get up that high he has to take off the ground with a significant amount of force. He also has to twist his body from moving sideways to moving vertically. Also, for most humans, their center of mass is located near their navel region. In Darius' exquisite high jump form, he makes sure to rotate his hips upward so that his center of mass is technically under the bar allowing the rest of his body to clear the bar afterwards. 

5) Category: Natural

Title: Technique of the Shot

Physics Concept: Force/ Kinetic Energy

Description of Photo: In this photo, my brother attempts a basketball shot. He follows the elements of a good shot perfectly.

Explanation of Physics: The shot in basketball is stuffed with physics that contribute to the ball going into the net. In this photo in particular, my brother needs to jump into the air in order to give him a better trajectory. So he exerts force on the ground to launch himself in the air. Next, when he is shooting, he needs the force in his arms to propel the ball towards the basket. Therefore, he winds his elbow back (which is his potential energy) so that when his elbow extends, its kinetic energy will cause the ball to travel towards the basket. Also, the force in which he propels the ball has a huge effect on whether or not the ball goes in. Since force equals mass times acceleration, he must accelerate the ball off his fingers well to use the correct force to make the ball enter the basket.

Rocket Report Rubric

I) Materials

3 two liter coca cola bottles -2.99 each

One cardboard box- 1.99

One roll of duct tape- 2.99

Two rolls of toilet paper- 0.99 each

One bag of cotton balls- 1.99

Two pages of printer paper- 0.10 each

A small garbage bag- 2.00

A few yards of string- 1.50

II) Procedure

First, we cut off the bottoms off of two of the bottles and the neck of just one of the bottles. Then, we took the only bottle that was not tampered which we did not tamper, and flipped it upside down, so that the neck was facing downwards. After, we duct taped the bottom untampered bottle to the bottle with no bottom or neck (which looked more like a cylinder). The main portion of our rocket was done. Then, we moved to building the capsule for the egg. To do this, we took the two bottoms of the bottle which we cut off earlier and discovered that they fit snugly inside of each other, so with some tape they could easily support the egg to keep it in place. We gathered the two toilet paper rolls and cut the rolls to fit inside the capsule and taped them to make sure they were secure. We used one of our own eggs to make sure the egg would fit. Once we were sure it did, we surrounded the toilet paper rolls inside the capsule with cotton balls. Lastly, we attached strings from the capsule to a small cutout of a garbage bag for a parachute. The capsule was complete. For finishing touches to the main rocket we cut out carboard and duct taped them to the sides of the rocket as wings. For style, we printed out pictures of famous physicists and taped them around the rocket. And the rocket was complete!

III) Results

Our rocket performed phenomenally. It was the second highest flying rocket in the class and managed to deploy its parachute at an optimal position. Many of the other rockets in our class failed to have their parachute deploy or did not reach 60 feet. In terms of weather, it was quite optimal due to the lack of wind to divert the rocket from its course. In our test launches, I found that when I did not fill up the rocket with a sufficient amount of water, it did not reach a high height. Therefore, our group ensured we filled up the rocket to at least 1/3 of the bottles capacity. We also made sure to be patient when putting the rocket on the launch pad to be sure that no water was wasted. And lastly, Kyle's work in pulling the lever at a good angle to prevent the string from jerking made for a smooth takeoff. As for the parachute, many groups chose to stuff their parachute into their rockets which although it did protect the egg somewhat well, did not allow for deployment. Therefore, we made sure to allow the capsule to fit loosely to the rocket and pack the parachute loosely into the rocket so that the deployment could be safe. We were extremely lucky for the strings of the parachute not to get caught on the capsule though. Finally, our rocket was extremely light compared to the heavy and bulky rockets of our counterparts which may have made a part in our success.

Youtube clip about our process from conception to launch:

http://youtu.be/imO83fcJ83o

IV) Conclusion

Given the success of our rocket, I believe it would be very hard to add too many improvements to the rocket. But I believe that if we strengthened the wings with some stronger cardboard that would have made a significant difference. In terms of the shape and size, I think we reached the optimal composition. But in terms of the weather, if it had a better upwind in order to create a better lift that would have been helpful, but otherwise the project went excellently.