If it's not moving at all at the beginning of the 10 seconds, then it falls 490 meters straight down in 10 seconds.
(Note: This is true of all objects on Earth . . . rubber balls, feathers, grains of sand, school buses, battle ships . . . everything.  As long as air doesn't hold them back.  Anything falling from rest falls 490 meters in the first 10 seconds.)
 
        
             
        
        
        
Answer:
Explanation:
a) 1.00 - 0.12 = 0.88
m = 1200(0.88)^t
b) t = ln(m/1200) / ln(0.88)
c) m = 1200(0.88)^10 = 334.20 g
d) t = ln(10/1200) / ln(0.88) = 37.451... = 37 s 
e) t = ln(1/1200) / ln(0.88) = 55.463... = 55 s