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TheSigFig

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  1. TheSigFig

    Its all relative

    By TheSigFig,

    Relative motion can be a bit weird when you really stop to think about it. It may seem to make sense that when we are standing still we don't move, but think about it. Why is it that we don't move when the earth is rotating really fast under us? Friction? Nope, that doesn't answer it. The reason is because while the earth is rotating, whatever point we are on, we move with the same tangential velocity of the earth. So while relative to the ground we may not be moving at all, relative to some observer in space (if we could be seen from space) we are actually moving pretty darn fast. It's the same reason why if you're in a car going 60 miles per hour and throw a ball straight up into the air it doesn't fly backwards. Relative to you, it's not moving at all, but relative to the ground, it's moving with the car at 60 mph. Just an interesting thought I had, and even if you read this thinking "well, of course that's how it works," just remember, to someone else, their mind may have just been blown. It's all relative
  2. TheSigFig

    Trampolines

    By TheSigFig,

    Trampolines are always a ton of fun, but they're one of those everyday things a lot of people don't really question. it's one of those things people just take as common sense, but what makes them work the way they do from a physics perspective? how is it that they can propel a person so high in the air, and why is it that jumping on one somehow sends a person higher than simply jumping on solid ground? the answer is that on a trampoline, there is an extra force acting on you each and every jump. as one lands from their first jump, the trampoline stretches downward a certain distance, extending springs along the outside. as they jump back up, there is an extra restoring force upward from the springs and trampoline added to the force of the person propelling themselves upward, resulting in a greater height achieved by the jumper. this force increases as the jumper applies more force to the trampoline as it is displaced a greater distance from its equilibrium position. Just jumping on solid ground doesn't get you any higher simply because the ground obviously doesn't move, so any extra downward force you exert might just result in sore feet after a while
  3. TheSigFig

    Driving and Dynamics

    By TheSigFig,

    After learning about and studying physics for a while, sometimes you just start thinking about how it applies to what you're doing right now. And while it may warrant a few odd looks from friends and family if you're like me and voice those sudden realizations, it can be quite fascinating, as there are some simple things that have some interesting explanations. Like how walking works because of a normal force the earth applies on you as your leg pushes down. As I was taking driving lessons one day, I started thinking of the way physics works when someone is behind the wheel. One thing noticed more was how when a car turns, the passengers tip over a bit in their seats to the other side of the car, and how when the car stops, everyone leans forward a bit. The reason this happens is because of inertia. Newton's first law states that an object in motion tends to stay in motion unless acted on by an outside force. When a car turns one way, say to the left for example after moving forward, your body wants to continue moving forward, but is dragged to the left by forces exerted by the seat on your body. This causes your body to tilt in the direction it was initially going, but because the car is turning, it appears to tilt to the side, in this case the right side since that is the side closest to the initial forward direction. The same thing applies as the car comes to a stop. As the car stops, your body wants to keep moving forward, but is held back by forces exerted by the seat and seatbelt opposing the direction of motion
  4. TheSigFig
    Conservation of momentum is a very important law. A rather interesting idea popped in my head earlier pertaining to this. Since momentum is conserved, wouldn't it be theoretically possible to lift off of the ground by hitting the ground fast enough with your hand? (Assuming you don't break something or get hurt.) If you're on a slippery surface or on something with wheels you can push off of a wall and slide in the opposite direction, so wouldn't something similar work vertically? Momentum is always conserved in an isolated system, isolated being the key word. This means that for momentum to be conserved there must be no net force on the system before or after the collision occurs. In the vertical direction, there is the force of gravity acting downwards on the system, so momentum is not conserved. So this crazy idea would not work. The reason momentum is conserved in the horizontal plane on the ground is because that force of gravity is canceled out by the normal force from the ground (or whatever surface it's on) making the net force before and after zero.
  5. TheSigFig
    With everyone waiting for December for the new Star Wars movie to come out in theaters, I thought I'd talk about some aspect of Star Wars in this blog. in this case, something that's common to a lot of works of science fiction: Spaceships, and the many capabilities they possess. First is their ability to simulate gravity. In the original Star Wars movies, the Empire utilizes massive space battleships called star destroyers, and despite them floating in space, the people on board seem to have no problem traversing their corridors as if there wasn't a lack of gravity, but how can something like that be possible? the answer is simple, it's not with today's technology. in order for something in space like a station or ship to simulate gravity, it must be very large, and rotating so that gravity is simulated by the object's centripetal force. in the case of the star destroyers, they may be massive, but they don't seem to rotate at all, meaning if one was somehow made today, anyone on it would just be floating around aimlessly, pushing themselves off of walls attempting to navigate it. Another notable aspect of spaceships in Star Wars and other works of sci-fi is their ability to travel at "warp speed" taking them across entire solar systems and galaxies in a matter of minutes. not only is this impossible because nothing can move faster than the speed of light, this would also mean that the ships would have to withstand an impossibly high amount of force to accelerate them to such a speed. so unfortunately, in today's age, long distance space travel is far from possible. perhaps in the future when more technology is created, it will be more viable. 

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