スピードガンで剛速球を測る！／Measure the Speed of a Fast Pitch with a Radar Gun
60.6 هزار بار بازدید -
2 سال پیش
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DENJIRO: A radar gun allows
DENJIRO: A radar gun allows you to measure the speed of a baseball or car. First, let’s try measuring something. It says 85 kph. A radar gun uses radio waves to measure speed. Let me explain in detail using a model. Say this potter wheel is a radar gun. When it spins, the strings attached to it move. I’m now going to place on the string little markers at even intervals. Think of these markers as radio waves. When the marker is about to hit a ball located on the other end, we place a marker at the same location on the side that’s coming back. This represents the radio wave’s reflection. Right now, the ball is not in motion. The wavelength of the radio wave that’s being sent out is the same as the wavelength of the radio wave that gets reflected and comes back.
Now, what will happen when the ball is approaching us? Like before, we place a marker on the other side when it reaches the ball. We can see that the intervals between the markers coming back are shorter. When the ball is coming toward the radar gun, the reflected radio wave’s intervals are shorter, and the frequency increases. The wavelength becomes even shorter if the ball moves faster. So a radar measures the frequency of the radio wave that comes back and converts it into a number.
Now, let’s try to measure the speed when the ball’s speed changes drastically.
BOY: It’s 180 kph!
DENJIRO: When the ball is attached to rubber, it rapidly accelerates from zero to about 100 kph. But the radar gun is still able to measure the speed because the radio wave reaches the gun at a speed of about 300,000 kps. While the ball is in motion, the gun sends out multiple radio waves and keeps measuring the speed. As a result, it’s able to measure the ball’s fastest speed.
I hope energy will bring you all happiness. Our magic word is "Happy Energy!”
Now, what will happen when the ball is approaching us? Like before, we place a marker on the other side when it reaches the ball. We can see that the intervals between the markers coming back are shorter. When the ball is coming toward the radar gun, the reflected radio wave’s intervals are shorter, and the frequency increases. The wavelength becomes even shorter if the ball moves faster. So a radar measures the frequency of the radio wave that comes back and converts it into a number.
Now, let’s try to measure the speed when the ball’s speed changes drastically.
BOY: It’s 180 kph!
DENJIRO: When the ball is attached to rubber, it rapidly accelerates from zero to about 100 kph. But the radar gun is still able to measure the speed because the radio wave reaches the gun at a speed of about 300,000 kps. While the ball is in motion, the gun sends out multiple radio waves and keeps measuring the speed. As a result, it’s able to measure the ball’s fastest speed.
I hope energy will bring you all happiness. Our magic word is "Happy Energy!”
2 سال پیش
در تاریخ 1401/08/27 منتشر شده
است.
60,617
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