ANSWERS 



TO THE 



PEACTICAL QUESTIONS AND PEOBLEMS 



IN THE 



FOURTEEN WEEKS COURSE IN PHYSICS, 



MOTION AND FORCE. * 



37. 1-37. (See pp. 15-19 of this Key for Answers to 

 these Questions.) 



38. If a 100 horse-power engine can propel a steamer 5 

 miles per hour, will one 0/200 horse-power double its speed? 



By no means. Resistance is proportional to zf*. (See 

 Physics, p. 26.) To double the velocity would require 

 over 400 horse-power. (See note, p. 27.) 



39. Why is a bullet flattened if fired obliquely against 

 the surface of water ? 



" Because the particles of the ball which strike the 

 water are impeded in their course by the particles of 

 water with which they come in contact, and are driven 

 back upon those lying next to them, before the motion of 

 the ball can be imparted to the water " A. B. Watkins. 



