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Homework Help: Physics Concepts

  1. Dec 19, 2003 #1
    How am I supposed to figure out these concepts? No problems to do, but I'm just not understanding the material/concepts? anyone care to explain/teach me?

    5.) Weight of a man who is throwing a bag of potatoes?

    7/8) Net acceleration of a body on a curved path

    10) Kinetic energy of a rocket after firing its engine

    14) Acceleration of a point on a wheel

    18) kinetic enregy expressed in terms of momentum

    19) distance traveled & energy lost by skier

    20) escape speed for spacecraft

    21) tension and agular speed of a rock on a string

    22) trajectories after a football tackle

    23) power wasted by falling water
     
  2. jcsd
  3. Dec 19, 2003 #2
    The weight of the man does not increase. However, the normal force exerted by the ground on the man increases. This is because the man must exert a force F on the potatoes to throw it into the air. The potatoes exert the same force F on the man. So the net force acting on the man is his weight W plus F. Since the man does not accelerate, the normal force must be the same. So the man may feel heavier, but his weight is the same.

    I need more information than this. ANY body can be said to be traveling on a curved path.

    Again, I can't describe this without more information. Is the speed constant?
     
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