Drums

So I was at my friends house the otherday watching is one guy playing the drums. When he hit the drums with a stick some force is transferred to the drum and some is pushed back on the stick repeling each other. Yet the force in the drum of the reverberation starts to deminish. The reason is the Kenetic Energy lost so sound. As sound is created the drum heads exert a force on the air creating waves we hear as sound. This is why when you hit a drum you hear sound, and why the drum wont vibrate forever. Some kenetic energy is lost due to sound in the collision and air resistance. When you hit the drum the stick will bounce back but it will have less momentum and Kenetic Energy that it previously had. The energy is lost from the sound of the collision and the air resistance.

Thanks for reading, Mark.

Baseball

So I was watching the Rays versus Sox game this afternoon when I saw Pedroia hit a homerun in the top of the first inning. Then I realized that you could calculate the amount of momentum needed to hit the ball over the center field fence, if you knew the mass of the ball and the height of the fence, and the angle its hit at. By taking the angle its hit at and the length and height, you could use the range equation and solve for the initial velocity of the ball. Then you could use this velocity to find the momentum of the ball and finally the bat. The calculation isn’t completely correct because of air resistance and such but it should be fairly close. The collision should be inelastic because you lose some kinetic energy to the reverberation of the bat as well as the heat and spin of the ball. If you really wanted to have fun you could take into account those factors.

Thanks for reading; I’m going to sleep… Mark.

Momentum!

So the other day I was driving my 50kg RC car down a flat surface, equating my friction with the force of my engine staying at the speed limit of 2 meters per-second when I saw another vehicle moving toward me. IT was coming FAST at like 100 meters per-second and I judged it to be about 1kg. My RC car suddenly stopped on impact, with the 1 kg beetle replica. My Hummer RC car’s momentum was equal to the Beetle RC car’s momentum. These momentums allowed both cars to come to a stop when they struck. This is because the little mass of the Beetle had a big velocity while the big mass of the Hummer had little velocity. The equal momentum caused both to stop. But now that I think of it, it wouldn’t be fun to come to a sudden stop at 100 m/s, that might hurt.

Thanks for reading, Mark

Potential

So I was at someone’s 16th birthday party this past weekend and I was holding a water bottle in my hand when I thought of potential energy. That if I’m doing work by lifting up the bottle, where does it all go? Well it goes to potential energy. Im adding potential energy by doing work by lifting the bottle vertically. The work being h(mg) in this case. By lifting the bottle I gave it potential energy, to fall that if I drop it the amount of work coming out would be similar to the amount of work put in. The only difference would be air resistance and the like. The potential energy I put on the bottle was the change in height due to lifting multiplied by the net force being g*m. The idea of potential energy continues to make the world go round by keeping energy conserved. The work I put in to it will be changed to kenetic energy when the bottle lowers in height.

Thanks for reading, Mark