ACTION AND BEACTION, 



G9 



Fig. 37. 



To what will 

 the shock of 

 collision of two 

 bodies coming 

 in contact be 

 equivaleut ? 



the mass will be its momentum divided hv the quantity of matter, or 1 2 di- 

 vided bv 6, which is 2.* 



If two non-elastic bodies, as A and B, Fig 37, be suspended from a fixed 

 point, and the one be raised toward Y, and the other toward X, an equal 

 amount, they will acquire an equal force, or momentum, in falling down the 



r , . .1, arc, provided their masses are equal ; 



txplain the re- . ~i > 



Buitsof thecoi- and will bv contact destroy each 

 lie bodiir^' otl^^'^'s motion, and come to rest. 

 If their momenta are unequal, they 

 wUl, after contact move on together, in the direction 

 of the body having the largest quantity of motion 

 with a momentum equal to the difierence of the 

 momenta of the two before collision. 



143. The force of the 



shock produced by two 



equal bodies coming in, 



contact with equal velocity, 

 will be equal to the force which either, being at rest, would 

 sustain, if struck by the other moving with double the 

 velocity ; for reaction and action being equal, each of the 

 two will sustain as much shock from reaction as from ac- 

 tion. 



If a person running, come in contact with another who is 

 standing, both receive a certain shock. If both be running 

 at the same rate in opposite directions, the shock is doubled! 



In combats of pugilists, the most severe blows are P oo 



those struck by fist against fist, for the force sustained 



by each in such cases, is equal to the sum of the 



forces exerted by the two arms. If two ships, mov- 

 ing in contrary directions at the rate of 20 miles per 



hour, come in collision, the shock will be the same as 



if one of them, being at rest, were struck by the 



other, moving at 40 miles per hour. 



144. If we suspend two balls of 

 some non-elastic substance, as clay or 

 putty, by strings, so that they can 

 move freely, and allow one of the 

 balls to fall upon the other at rest, it wiU communicate to 



it a part of its motion, and both balls, after collision, will move on together. 



Illustrate this 

 principle. 



If one inelastic 

 body comes i:i 

 contact with 

 another at rest, 

 what occurs "? 



• This whole subject, nsnally considered dry and nninteresting. will be found to possess 

 a new interest, if the student will mike himself a few simple experiments, by suspending 

 leaden balls by the side of a graduated arc. as in Fig. 37, and allow them to fall under 

 different conditions. The length of the arc through which they fall will be fouud to be 

 an exact measare of the furcu with which they will strike. 



