General Physics I  
PHYS 121  
   Adventist University
Lawrence E. Turner, Ph.D.
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If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words:
Then shalt thou delight thyself in the LORD; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: .....
Isaiah 58:13-14  


Lab Activity

ballistic pendulum

This lab activity is to use a ballistic pendulum.

general objectives

  • determine the speed of a projectile
  • use conservation of energy and momentum

concepts and terms

  • conservation of energy
  • gravitational potential energy
  • conservation of momentum
  • inelastic collision


  • presentation
  • obtain experimental data and analyse them
The velocity of a ball impacting a ballistic pendulum with an elastic collision is given by:

v2  =  2 M2 gR(1 − cos θ)

where M is the mass of the pendulum and ball combined, m is the mass of the ball, R is the distance from the pivot to the center of mass of the pendulum and ball, and θ is the angle from the vertical reached by the pendulum when the ball collides with it.

Activity Report  due at the next class period—Wednesday

revised 4 Oct 11  
© 2007–2013, 2014 by Lawrence Turner