Week10 by shuifanglj

VIEWS: 44 PAGES: 14

									Week 10   1
          What is the strength of the gravitational
          force with which the Earth pulls on you?




     MEarth = 5.98x1024 kg
     REarth = 6.37x106 m




Week 10                                               2
Astrologers believe that the forces of the planets and stars at
the time of your birth determine key personality attributes and
your fate in life.
Could the force be gravity?
What is the gravitational force with which Jupiter pulls on you
when it is closest to earth?
What is the gravitational force with which the person next to
you pulls right now?

            MJupiter = 1.9x1027 kg
            djupiter = 7.78x1011 m
            dEarth = 1.5x1011 m


  Week 10                                                   3
Astrologers believe that the forces of the planets and stars at
the time of your birth determine key personality attributes and
your fate in life.
Could the force be gravity?
What is the gravitational force with which Jupiter pulls on you
when it is closest to earth? FJupiter on you = 2.4x10-5 N
What is the gravitational force with which the person next to
you pulls right now? Fclassmate on you = 3.8x10-5 N

            MJupiter = 1.9x1027 kg
            djupiter = 7.78x1011 m
            dEarth = 1.5x1011 m


  Week 10                                                   4
Week 10   5
   What is the escape speed of a particle on the
   “surface” of the sun?




Week 10                                            6
   Sagittarius A* is a bright radio source. What is the
   mass of Sag A*? How many times the mass of
   the sun is this?
                                     1 light day = 2.6x1013 m
                                   1 year  πx107 sec
                                   Msun = 2x1030 kg




Week 10                                                    7
Week 10   8
Week 10   9
          A particle is undergoing simple harmonic
          motion. What are its
             • Amplitude?
             • Period?
             • Angular frequency?
             • Maximum velocity?
             • Phase constant?




Week 10                                              10
          A 160 g mass on a 1.0 m-long string is
          pulled 6.7o to one side and released.
          How long does it take for the pendulum to
          reach 2.9o on the opposite side?




Week 10                                               11
          The 20 cm-long wrench in the figure
          swings on its hook with a period of 0.88 s.
          When the wrench hangs from a spring of
          spring constant 350 N/m, it stretches the
          spring 3.5 cm. What is the wrench's
          moment of inertia about the hook?




Week 10                                                 12
          The 15 g head of a bobble-head doll
          oscillates in SHM at a frequency of 4.0 Hz.

          * What is the spring constant of the spring
          on which the head is mounted?

          * Suppose the head is pushed 2.0 cm
          against the spring, then released. What is
          the head's maximum speed as it
          oscillates?



Week 10                                            13
Week 10   14

								
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