Question

An earth’s satellite moves in a circular orbit with an orbital speed 6280 ms^-1. Find the time of revolution.

• A. 130 min
• B. 145 min
• C. 155 min
• D. 175 min

Answer 1

Answer: (D)

175 min

Answer 2

v₀ = or r = $\frac { \mathrm { GM } } { \mathrm { v } _ { 0 } ^ { 2 } }$ and

T = $\frac { 2 \pi \mathrm { r } ^ { 3 / 2 } } { \sqrt { \mathrm { GM } } }$ = $\frac { 2 \pi \mathrm { GM } } { \mathrm { v } _ { 0 } ^ { 3 } }$

T = $\frac { 2 \pi \times 6.67 \times 10 ^ { - 11 } \times 6 \times 10 ^ { 24 } } { ( 6280 ) ^ { 2 } \times 6280 \times 60 } = 175 \mathrm {~min}$