torque

Like the example in my homework, I chose to talk about a light switch for this journal. While the light switch cannot do a complete rotation, it does go in half of a rotation when torque is exerted on it. To turn the lights on, the force exerted is positive, and thus it has positive torque. To turn the lights off, negative torque has to be exerted. The lever arm is the distance between the switch attached to the wall and the point where the finger hits it. As we learned, the greater the distance, the less force needed to flip the switch. This is why it would make more sense to flip the switch at its tip rather than the point closest to the wall. (Although it takes relatively little force to begin with, hitting the switch at the tip makes the task even easier to do!)

tests and washing machines

After the test, I kept thinking about that problem with the washing machine so I took a good look at the one I have at home. In a sense, the physics behind a washing machine is the same for that gravitron ride. The clothes push against the side of the machine, which results in a normal force pointing towards the middle. This normal force is also the centripetal force in the spinning action (and is equal to mass x centripetal acceleration). The holes on the side are for the water to leave at a tangent (because the water does not have enough force to keep it going in a circular motion). Also, because the motion is horizontal and not vertical, the centripetal force does not change throughout the motion. After seeing the real thing, answering the question seems a lot easier.