Wednesday, November 11, 2009

Projectile Motion: When Water Balloons Fly

Projectile Motion

One day, I was walking home from school when suddenly I heard a loud smack behind me. I turned around to discover that a water balloon had hit the pavement. Then, trying to find out what direction the balloon came from, I saw another and ran to avoid being soaked. As I looked at the direction it came from, I saw a small group of 4 or 5 people with a water balloon launcher and a huge bucket filled with the balloons. I saw them pull back the launcher and one yelled “PULL!” and I saw the balloon approaching with great speed. I was terrified and began to sprint when my jacket caught onto the fence next to me and I was stuck. I was terrified and anxious on whether I would get hit because I was a sitting duck. The balloon barely missed me. Unfortunately, I was still stuck and they had already loaded another balloon. I knew that there was only one way to find out how much time I had to escape the fence was PHYSICS! Fortunately, I had Physics class that day and we had just learned about projectile motion. I remembered that I could find how long the projectile, in this case a speeding water balloon, was in the air. I knew that their last miss would have been a direct hit if they had aimed right and saw that the launcher was at the same angle. I would have to base how much time I had left on the last shot. I could tell that I was about 24m from where the balloons were being launched and that it was being launched at an angle of about 15m/s at 45˚ in relation to the horizontal. I quickly thought through all the ways that I could calculate the time: t = x/Vocosθ or t = Vosinθ/g. Knowing what I was given I quickly decided the fastest way was t = x/Vocosθ. So I plugged in the distance, x = 24m, divided by Vo = 15m/s*cos45˚ which all came out to 2.3s. Once I heard them shout “PULL!” again, I knew I needed to act fast. Finally I broke free from the fence and sprinted away dodging the water balloon at the last second all because of PHYSICS!

Projectile Motion Voki

Projectile Motion Wordle

Here are some commonly used words when dealing with projectile motion. I used to make this.

Tuesday, November 10, 2009

Projectile Motion: When Water Balloons Fly... The Movie Physics project by thovyson69

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