• Why do storm clouds turn dark and grey?

    10 answers · 1 day ago
  • Is time travel possible?

    Best answer: Possible, but very, very, very, very unlikely, except through temporary wormholes on the Planck scale.
    Best answer: Possible, but very, very, very, very unlikely, except through temporary wormholes on the Planck scale.
    12 answers · 2 days ago
  • Is there less gravity at the north pole?

    Best answer: There is a greater gravitational attraction at the North Pole. Due to the rotation of the Earth, objects at the equator weigh slightly less. There is no rotational energy at the North Pole and that is why the force of gravity is greater.
    Best answer: There is a greater gravitational attraction at the North Pole. Due to the rotation of the Earth, objects at the equator weigh slightly less. There is no rotational energy at the North Pole and that is why the force of gravity is greater.
    7 answers · 1 day ago
  • Isaac did not discover gravity?

    Best answer: BS. Newton knew that it took a force to move things in a circle. He was pondering what might be the force that kept the moon in orbit. When the apple fell he suddenly realized that the force MIGHT be gravity. He rushed back and wrote down his thoughts. When applied to the knowledge of Kepler he came up with the... show more
    Best answer: BS.
    Newton knew that it took a force to move things in a circle. He was pondering what might be the force that kept the moon in orbit.
    When the apple fell he suddenly realized that the force MIGHT be gravity.
    He rushed back and wrote down his thoughts.
    When applied to the knowledge of Kepler he came up with the empirical law that the force could ONLY be gravity if it reduced with distance yet increased with masses.
    ie F is proportional to Mm/ R^2
    If that was not true then gravity could not be the force involved.
    The test was left to Cavendish many years later.
    8 answers · 2 days ago
  • Physics question: Why do rockets work in space?

    Best answer: Think of the "kick" from a rifle or shotgun - that happens before anything leaves the barrel and is nothing to do with air resistance or even being in an atmosphere. Simply, if you push or throw something away from you, the force you exert on that is equally pushing you in the opposite direction. For a... show more
    Best answer: Think of the "kick" from a rifle or shotgun - that happens before anything leaves the barrel and is nothing to do with air resistance or even being in an atmosphere.

    Simply, if you push or throw something away from you, the force you exert on that is equally pushing you in the opposite direction.

    For a given amount of force that can be a heavy mass thrown slowly or a light mass thrown at high speed - and a rocket engine is expelling a lot of gas at extremely high speeds.


    If you want a simpler action<>reaction demo, just sit in a swivel chair that spins easily and put both your arms as far to the same side (eg. left) as you can - them move them both, fast, as far across the other side as you can.
    Your body will turn slightly the other way in reaction; it's rotational rather than linear but the same effect (and it stops at the end of your arm movement as you are not "throwing away" your arms....)

    If you hold something heavy while doing that your body will turn more.

    For proof it's not air resistance you could compare holding an inflated balloon to holding a smaller but very heavy weight.
    15 answers · 4 days ago
  • Say you had a stick that was extremely long, could it break the laws of physics?

    If I had a stick that was one light year long, and somehow I was able to change the orientation of the stick, would the opposite end, move faster than the speed of light? Because lets say you had a ruler that was 1 meter long, and you hold it from one end and start moving it, the opposite end moves much faster... show more
    If I had a stick that was one light year long, and somehow I was able to change the orientation of the stick, would the opposite end, move faster than the speed of light? Because lets say you had a ruler that was 1 meter long, and you hold it from one end and start moving it, the opposite end moves much faster than the end you are moving it from. (If my question makes any sense at all)
    8 answers · 2 days ago
  • Do tall skinny or short overweight people have more air resistance against gravity on a freefall?

    Best answer: With the assumptions of oldprof, the person with the greater mass/crosssectionalarea will have the greater acceleration.
    Best answer: With the assumptions of oldprof, the person with the greater mass/crosssectionalarea will have the greater acceleration.
    5 answers · 17 hours ago
  • Shouldn't the ball falling down take less time than the ball going up ?

    Best answer: Taking upward quantities as positive and assuming that there is no air resistance, the case is: An upward force, Fu, is applied to the ball in a very short period of time to make the initial velocity u. Then, in the whole journey, the only force acting to the ball is -Fg (i.e. acceleration a = -g), which makes the... show more
    Best answer: Taking upward quantities as positive and assuming that there is no air resistance, the case is:

    An upward force, Fu, is applied to the ball in a very short period of time to make the initial velocity u. Then, in the whole journey, the only force acting to the ball is -Fg (i.e. acceleration a = -g), which makes the ball decelerates to stop, and then falls down to the original position.

    In the going up journey, the initial velocity vₒ= u, the acceleration a = -g and the final velocity is v = 0.
    In the going down journey, the initial velocity vₒ= 0, the acceleration a = -g and the final velocity v = -u.
    Applying the formula: v = vₒ + at, the time for ball moving up = time taken to fall back down.
    6 answers · 2 days ago
  • Can impulse's unit be Kg. m/s?

    Can it be kg. m/s? or is always N.S newtons seconds
    Can it be kg. m/s? or is always N.S newtons seconds
    7 answers · 2 days ago
  • Is Backward Time Travel Possible?

    5 answers · 2 days ago
  • Are most collisions elastic or inelastic?

    Are most collisions elastic or inelastic?
    Are most collisions elastic or inelastic?
    6 answers · 3 days ago
  • Explain why the average power delivered to a resistor is not zero?

    The average current in a resistor in an ac circuit is zero. Explain why the average power delivered to a resistor is not zero.
    The average current in a resistor in an ac circuit is zero. Explain why the average power delivered to a resistor is not zero.
    6 answers · 3 days ago
  • Why do things fall to the ground ?

    Best answer: We firstly note that they DO fall to the ground. Then we make a definition of this mysterious stuff. We call it gravity. We then make extensions and predictions based on that. We discover what affects it. What we do NOT know, and never will, is WHY gravity exists. Nor WHY energy should be conserved or WHY F =... show more
    Best answer: We firstly note that they DO fall to the ground. Then we make a definition of this mysterious stuff.
    We call it gravity.
    We then make extensions and predictions based on that. We discover what affects it.

    What we do NOT know, and never will, is WHY gravity exists.
    Nor WHY energy should be conserved or WHY F = ma

    Why is never an issue for a scientist. It is only an issue for philosphers and religious people.
    11 answers · 5 days ago