# math

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a spaceship leaves the alien mother-ship and begins descending to earth. it descends 64m during the first second and 7m less during each second afterward. if the aliens invade after 10s, how far did the ship descend?

• math - ,

Vi = -64 m/s (velocity is down)
dv/dt = a = +7m/s^2 (acceleration is up)

h = hi + Vi t + (1/2) a t^2
h - hi = -64(10) + 3.5 (100)
= -640 + 350
= - 290
so it went down 290 meters

• math - ,

would there be any formulas you would have to use to get this answer for grade 11 math

• math - ,

h = hi + Vi t + (1/2) a t^2
usually
x = Xi + Vi t + (1/2) a t^2

• math - ,

In first one second it descends 64 m ,
Next one second it descends =(64-7)=57 m
Then next one second it descends = ( 57-7)=50 m,
4th second it descends =50-7=43 m
5th second it descends = 43-7=36 m.
6th second it descends = 36-7=29 m.
7th second it descends = 29- 7= 22 m
8th second it descends = 22-7=15 m
9th second it descends = 15-7=8 m.
10th second it descends = 8-7=1 m

Total distance covered by it= 64+57+50+43+36+29+22+15+8+1= 325 m