Corrigé 2

ρ=masse
volume .
V=4
3πr3r= 8.7·10−15 m
⇒ρ=3.5·10−25 kg
4
3π(8.7·10−15 )3m3= 12.7·1016 kgm−3
0◦kgm−3
ρ
ρeau =12.7·1016 1000 = 12.7·1013.
ρor = 190300 kgm−3
d= 10 µ l = 10
V=d·l2= 10−7m3
m=ρorV= 190300 ·10−7kg = 1.93 g
Pmg
N
f
fem
N
N
V
P
10
fem
f

N w
w
fc
Tmax = 10000 m~amax +m~g =~ Tmax ⇒amax =Tmax −mg
m
m~g = 8000 m= 816,33 amax = 2,45 ms−2
F(r) = GmM
r2G= 6.67·10−11 Nm2kg−2r
F(4RT) = GmM
(4RT)2=GmM 16R2
T
=1
4F(2RT) = 360000 N.
mgT= 800 ⇒m=800
gTmgM= 800gM gT= 295.2
we=mg −ma =mg −m(3g) = −2mg
~we=−2~w
w= 100 µs= 0.3
µsN|N|=|w|Fmin = 0.3·100
Fmin = 0.3·10000
F0
min = 0.15 ·10000
ρ= 1017 kgm−3R= 1 r= 0.01
m=ρV =ρ4
3πr3= 4.19 ·1011 kg.
w=mg = 4.11 ·1012 N.
Fatt =Gm1m2
R2=Gm2 R2= 1.17 ·1013 N.