5 Matching Annotations
  1. Mar 2017
    1. People that do the activity of parkour are athletic humans capable of controlling their body and using it to the fullest extent. Numerous people hang off of buildings or do handstands with one hand on the edge of tall buildings which show great stability. A person that does a handstand on an edge of a tall building has great strength as well as stability because of their form. Their center of gravity is on the arm that is holding them up, and they are able to stabilize themselves by moving their other arm as well as their legs in a position that "pushes" all the weight onto one spot allowing them to balance.

  2. Feb 2017
    1. Eddie Hall, the strongest man in the world is the first man to lift 500kg. That itself is an amazing feat, and by using the height of the 500kg in relevance to the ground, we can calculate the work lifted. Eddie Hall's height is 6ft 3, and since deadlifts require the person to lift a bar at their torse, we can estimate the lift height to be 3 feet or .91m. Knowing that the weight is (500kg)(9.8N), we can do (500kg)(9.8N) (.91m) to get 4459J which is the work lifted.

    1. The formula for Kinetic Energy is 1/2 m v^2. Based on this site, the average speed of a pitch by a 16 year old is 76 MPH. Based on this data, we can find the Kinetic Energy of a 16-year old's pitch by doing KE = 1/2 (.145 KG) (76^2) = 418.76 J

    1. Mountain climbers and skydivers experience GPE. You explained that GPE = (mass) (gravity) (height), and I agree with you that formula is correct. You then gave an even better explanation using someone on top of Mount Everest, and you said that the person's GPE was 7,370,384 J which is calculated from the height which is 8848 x the force 9.8 x 85 which is his mass. The GPE calculation is also different from someone on a ground since they have a different height.

    1. The idea of the Earth actually being flat is an interesting topic. You brought up the fact through a simulation of a flat-Earth that the farther a person would travel to the end of the flat-Earth, it'd be harder to walk as if we were walking up hill. The only question I have about this flat-Earth theory is if the Earth were flat, why do we view it as round from Space. I do agree with you that measuring smaller distances makes it seem as the Earth is flat, and that larger distances makes the actual Earth seem round. You questioned the fact that if the Earth was flat, the gravity of the center of this disc-shaped Earth would be different, but you also brought up another theory which was that the Earth was accelerating upwards at 9.8 N, so the gravity we know today is nonexistent. This was very interesting, and brought up a new perspective on how the Earth was seen. You ended on the fact that it is unknown to us if the Earth is actually flat or round based on the many perspectives, and that it may take millions of years for the answer to be found. My last note on this theory you brought up is that, if the Earth were moving up 9.8 N, it makes sense that if we had our own gravity which moved 9.8 N down to the center, that we do not realize this because they both cancel each other. The only thing I'd like to inquire is why we do not see the actual force applied on Earth from Outer-Space. It's a very far out theory that in my mind gets debunked based on information we receive from space.