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Author Question: A karate master strikes a board with an initial velocity of 12.0 m/s, decreasing to 3.0 m/s as his ... (Read 112 times)

humphriesbr@me.com

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A karate master strikes a board with an initial velocity of 12.0 m/s, decreasing to 3.0 m/s as his hand passes through the board. If the time of contact with the board is 0.002 s, and the mass of the coordinated hand and arm is 1.0 kg, what is the force exerted on the board?
 a. 7.5E+3 N
  b. 1.8E2 N
  c. 3.0E2 N
  d. 4.5E+3 N
  e. 6.0E+3 N

Question 2

A boxcar of mass 125 tons at rest becomes uncoupled on a 2.0 grade. If the track is considered to be frictionless, what speed does the boxcar have after 9.0 seconds?
 a. 4.0 m/s
  b. 0.038 m/s
  c. 31 m/s
  d. 3.1 m/s
  e. 0.31 m/s



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Answer to Question 1

d

Answer to Question 2

d





 

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