Read the summary and the most important questions on phy pw ch7 | veerle

• 2 remember

  This is a preview. There are 2 more flashcards available for chapter 2
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• 5 different types of forces: (there are more)

  1. gravity, wieght and muscle force.
  2. mucles force and spring force.
  3. gravity and magnetic force.
  4. gravity.
  5. wind force.

• 3 important questions

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• (9a) Name 4 forces that you deal with when cycling to school:

  muscle power, gravity (up and down hill), wind force and friction.

• (9b) Think of two applications of magnetic force.  

  fridge magnets, a compass

   

• (11a) At which point during the motion of a swing are you weightless?  

  At the two highest points of the motion of the swing you are weightless.

   

• (11b) Explain if gravity is at work at that moment.

  Gravity still acts upon you, but you exert no force (weight) upon the swing.

• (13) Explain with sketches how your centre of gravity changes if you are carrying a heavy backpack.  

  The centre of gravity becomes higher, so in order to stay balanced you have to bend forwards. 

• (19a) show in one sketch the effect of gravity on the gymnast, which is 650 N. use the force scale 1cm =100 N (19b) show in the other sketch the weight of the gymnast. use the same force scale.

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• (24a) How could your mass change?

  for example by eating less or more, or exercising less or more.

   

• (24b) Give two reasons why the force due to gravity on you might change.

  becaus your mass changes (see 24a) or becaus you go into space.

   

• (24c) What is an easy way to be weightless for a short time?

  by jumping in the air. as long as you are not touching the ground, you are weightless.