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danvan13

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danvan13 last won the day on May 25 2015

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  1. danvan13

    Sonic Boom

    Sonic boom that is produced by an aircraft or other object flying at a speed equal to or exceeding the speed of sound(331 m/s) and that is heard on the ground as a sound like a clap of thunder. When a plane or other aircraft travels at subsonic speed, the pressure disturbances, or sounds, that it generates extend in all directions. Thus why you get the cone that flows around the aircraft. The intensity of the sonic boom is determined not only by the distance between the craft and the ground but also by the size and shape of the aircraft, the types of maneuvers that it makes, and the atmospheric pressure, temperature, and winds. If the aircraft is especially long, double sonic booms might be detected, one emanating from the leading edge of the plane and one from the trailing edge.
  2. danvan13

    Sonar waves

    Sonar is an acoustic wave (whose uses are roughly analogous to radar) and whose name is an acronym for "sound navigation and ranging." Sonar consists of pulses of sound waves are transmitted into water, usually at ultrasonic frequencies in the range of 20-100 kHz. They travel out and are reflected by a solid object. The reflected signals are detected and then correlated to give the operator an indication of the distance and bearing of the object. There are some fundamental differences to note between sonar and radar. First, the frequencies used for sound are much lower, since sound is highly attenuated at frequencies higher than 100 kHz. Secondly, the speed of sound (331m/s) in water is much slower than that of a radio wave in air, so the time between the transmitted and received pulses is much greater for sonar. Thus the correlation needed to determine bearing is different. Thirdly, the speed of sound in water varies with depth, temperature, and even salinity, and all these parameters need to be known for accurate determinations.
  3. We all know when we throw a snowball we apply a force to it and when it hits somthing that other object is applying the same force that the snowball applied to it. So if Seth throws a snowball at Joe and it hits Joe in the face. Joe's face applied a force to the snowball and the snowball applied the same force to Joe's face.
  4. danvan13

    Speakers

    The physics behind speakers is quite amazing. The speaker consits of 3 parts. The cone, The coil, and the permenant magnet. The electro coil will recive a pluse of electricty and that will make it be drawn to the permenant magnet and will make the cone vibrate which sends vibrations into the air which the ear will recive.
  5. hmmm... similar to why a golf ball spins and curves.
  6. Don't forget when a car explodes most of the time the bodies fly towards the explosion.
  7. In my previous blog post I had a question to find the final velocity of my phone before it hit the floor. Assume the locker shelf is 1.8m high. Now we will be able to find the final velocity using the formula vf^2=vi^2+2ad. vf^2=0^2+2(9.81m/s/s)(1.8m). vf^2=2(9.81m/s/s)(1.8m). vf^2=35.316m^2/s^2. Square root vf^2= Square root 35.316m^2/s^2 vf=5.9m/s. My phone hit the floor with a velocity of 5.9 m/s.
  8. Recently I have gotten a new old phone. This is because my old galaxy Broke. Well it did fall out of my locker in the pool and land on the tile floor and shatter. There are lots of physics that are involved here. Knowing the height of the locker shelf, and the acceleration due to gravity (9.81m/s^2), and the starting velocity we will be able to find the final velocity before it hit the ground and it broke.
  9. During soccer season I have had to stop all kinds of shots from m team and other teams as well. The physics behind stopping a shot is the force of which you apply to the ball. Newtons 3rd law states that forces come in pairs and that for every force there is and equal force acting against it. In this case force 1 would be the soccer ball hurling at me and the force that would be acting against it once it hits me would be my hands. So the force that I apply to the ball has to be equal to the balls force that it is applying to me. So to get the ball to stop and not go into my net I need to exert a force greater than the ball is applying so that then I am able to catch it or have it bounce off myself in the opposite direction. It also helps to have sticky gloves.
  10. When the club head hits the ball the club head is rotating around the center of gravity axis which is in the middle of the club. When the head rotates and hits the ball the gear effect comes into play. The gear effect is thinking of the golf ball as one gear and the face of the driver as another gear. So as you hit the ball if you catch it on the toe then the ball will slice and have side spin moving to the right of the hole and if on the heel of the driver you will hook it so the ball curves to the left of the hole. So if you hit it right inside the center of gravity on the club then the ball should go straight. There is also a second curve to the club not just horizontal but vertical. The vertical curve defines the launch angle of the ball of the face of the club. Again the center of gravity is the key spot to hit it. If you hit it to high up on the club face then it will pop up into the air, and to far down on the club face then it will be forced into the ground a few meters in front of you.
  11. Why do golf balls have dimples in them? Dimples in the golf ball cause it to fly further than a smooth ball. When hit the smooth ball will not generate enough lift to go far. The shape when hit will be a parabolic shape. Dimples in a golf ball even tho the dimples cause drag it is not enough to hurt the flight of the ball. With the dimples impressed on the golf ball, the ball will generate more lift than a smooth one. When hit the magnus lift, force on the golf ball cause it to curve slightly upward. This is caused because the drag on the top of the ball is less than the drag on the bottom. So the air moves faster over the top part than the bottom. Thus this also causing the shape of flight that the ball has during its travel. In all golf balls have dimples so that the player will be able to hit it further with less drag. Fun fact: Early golfers figured this out when the hit a rough chewed up ball further than a new smooth one.
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