166 LABORATORY LESSONS IN GENERAL SCIENCE 



tive values of the velocities of P (Pv) and of W (Wv) in 

 all cases ? 



What are the relative values (a) of P times Pd, and W 

 times Wd ; (b) of P times Pv, and W times Wv ? 



(b) With the Cord Attached to the Movable Pulley 



7. Make two other drawings to show the arrangement 

 of pulleys, and the values for P and W as directed in para- 

 graphs 1 and 2 above, but this time with the end of the cord 

 attached to the movable pulley. 



8. Determine the values, and state the relationships 

 now apparent as required in paragraph 4 above. 



9. Answer the same requirements as in paragraphs 5 

 and 6 above, with the conditions as they are now. 



10. Disregarding any waste of energy due to friction, 

 what seems true of the relative value of the work done 

 (W times Wd), and of the energy used in doing this work 

 (P times Pd) ? 



11. State some of the advantages from the use of pulleys 

 as machines (a) over the direct application of any force to a 

 body that is to be moved ; (b) over the use of levers of any 

 kind. 



