Re: CyBookie - Plane on a Treadmill
Get yourself a 3 ft long bungee cord, a toy tractor, and a treadmill. Fasten one end of the bungee cord to the wall, at about the same level off the ground as the top of the treadmill belt. Fasten the other end of the bungee cord to the front or rear of the toy tractor, as if you were going to use the bungee cord to pull the tractor around the room. Position the back end of the treadmill 6 ft from the wall, with the front of the treadmill pointing towards the wall to which the bungee cord is attached.
Put a mark of chalk on one of the tractor tires. With the treadmill off, stretch out the bungee cord and set the tactor on the back treadmill belt. As the bungee cord pulls the tractor along the treadmill belt towards the wall, count the number of revolutions that the tire makes.
Next, do the same thing again, exept this time, turn the treadmill on full blast. Presto!! When you set the tractor on the moving treadmill, the bungee cord still pulls the tractor towards the wall, against the movement of the treadmill, but the number of tire revolutions you count will increase. (EDIT- If the tractor isn't very heavy, the bungee cord will probably be strong enough to break the friction force between the tractor tires and the rolling treadmill belt, so the tractor might actually be sliding along the treadmill belt.)
This is anlogous to the airplane on a treadmill, except in the case of the airplane, the thrust of the high speed air (in the case of a prop plane) or air/exhaust gasses (in the case of a jet engine) are pushing the plane forward, instead of the bungee cord pulling the plane forward. The wheels of the airplane or the wheels of the toy tractor have nothing to do with imparting motion to the object.
No the plane is not moving forward. If you we standing next to the treadmill with the plane on it both moving in opposite directions at the same speed the plane will not move forward away from you just as you have no forward movement when you are running on a treadmill because your both going at the same speed.
Get yourself a 3 ft long bungee cord, a toy tractor, and a treadmill. Fasten one end of the bungee cord to the wall, at about the same level off the ground as the top of the treadmill belt. Fasten the other end of the bungee cord to the front or rear of the toy tractor, as if you were going to use the bungee cord to pull the tractor around the room. Position the back end of the treadmill 6 ft from the wall, with the front of the treadmill pointing towards the wall to which the bungee cord is attached.
Put a mark of chalk on one of the tractor tires. With the treadmill off, stretch out the bungee cord and set the tactor on the back treadmill belt. As the bungee cord pulls the tractor along the treadmill belt towards the wall, count the number of revolutions that the tire makes.
Next, do the same thing again, exept this time, turn the treadmill on full blast. Presto!! When you set the tractor on the moving treadmill, the bungee cord still pulls the tractor towards the wall, against the movement of the treadmill, but the number of tire revolutions you count will increase. (EDIT- If the tractor isn't very heavy, the bungee cord will probably be strong enough to break the friction force between the tractor tires and the rolling treadmill belt, so the tractor might actually be sliding along the treadmill belt.)
This is anlogous to the airplane on a treadmill, except in the case of the airplane, the thrust of the high speed air (in the case of a prop plane) or air/exhaust gasses (in the case of a jet engine) are pushing the plane forward, instead of the bungee cord pulling the plane forward. The wheels of the airplane or the wheels of the toy tractor have nothing to do with imparting motion to the object.
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