Knowing that the velocity of an experimental space probe fired from the earth has a magnitude v A 32.32 32.5 Mm/h at point A, determine the velocity of the probe as it passes through point B.
vA
hB = 12 12700640 km
km
B vB
SOLUTION rA
hA R
rA
10.69Mm Mm 10.67
rB
4.32Mm 6.37 4.3 Mm +6.37 MmMm
hB R
72.7 MmMm 6.37 MmMm 12.64 + 6.37
rB
19.07 Mm 19.01 Mm
At A,
vA TA
1 2 8978 m/s m 9028 2 VA
rA R
32.5 MMm/h m/h =9028 m/s 32.32 8978 m/s
gR 2m rA
GMm rA
10.69 u 106 m 10.67
10.69 M Mm 10.67 m
6370 km
6
40.302 xu 10 40.752 106mm
6.37 u 106 m
9.81 m/s 6.37 u 10 m 10.69 u 10 m 10.67 2
VA
At B
rB
1 2 mvB ; VB 2
37.237 u 106 m 37.306
gR 2m rB
GMm rB
9.81 m/s 6.37 u 10 m 19.01 u 10 m 19.07 6
2
m
6
6 20.939 u 10 m 20.874
40.302 u 106 m 37.306 37.237 u 106 m TB VB ; 40.752
vB2
m
6 19.01 u 10 m 19.07
19.01 19.07 Mm Mm 2
TA VA
2
6
TB
VB
6
1 2 20.939 u 106 m mvB 20.874 2
37.237 u 106 20.939 2 ª¬40.302 40.752 u 106 37.306 20.874 u 106 º¼