Question

How long will it take to reach mars from the Earth?

• A. $8$ days
• B. $6$ days
• C. $60$ days
• D. $80$ days

Answer 1

Answer: (D)

$80$ days

Since the orbital radius of earth is $1.5\times {10}^{11}m$, during closed approach, distance between earth and mars is $d=2.28\times {10}^{11}-1.5\times {10}^{11}m=7.8\times {10}^{10}m$.

Since escape velocity from eartn is $11200m/s$, required time is,

$t=\frac{7.8\times {10}^{10}}{11200}=80days$