Recent content by rc1234

  1. R

    How increased mass and drag affect speed

    Hello. I read an article about aerodynamics. http://www.cyclist.co.uk/in-depth/2873/fat-v-skinny-who-goes-downhill-faster I'm a little bit confused with this statement regarding mass, drag, and velocity: "When you increase the mass the speed increases by cubic function, whereas if you...
  2. R

    I Sled Physics -- trouble understanding this equation

    I guess I should've been more clear. I said two different systems because what I meant was the man who pushes the sled stops pushing once the friend+sled (yes, they are one body) gains momentum. Thank you for clarifying and providing solution options. I'll use that advise on my future posts.
  3. R

    I Sled Physics -- trouble understanding this equation

    I just realized how they are different systems. The first is the one between the person pushing and the person on the sled. The second is the person on the sled and the snow. Therefore, it doesn't make sense to include the push force in the second reference frame. Last time I took Physics...
  4. R

    I Sled Physics -- trouble understanding this equation

    I'm sorry I am still confused. I understand friction has its own calculation, (friction coefficient*normal force) but I'm talking about the sum of the forces as a whole. The F = Weight-Friction makes sense if the reference frame starts from the time it instantly slides down the slope to the...
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    I Sled Physics -- trouble understanding this equation

    In the classic example of a man on a sled being pushed down a hill, the equation involves the forces of gravity and friction: F = weight - friction or F = ma = mgsinθ-μkmgcosθ I do not understand why the push force at the start is not included in the equation. I assume that push force would...
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