The mars rover opportunity approached Mars on January 24th, 2004 and was moving with a velocity of 5.4km/s when it hit the atmosphere on its way to the surface at Miridani Planum.

Question

i)convert this speed to miles/hr.
ii) If it took the lander 6 minutes to hit the surface of Mars, what is the maximum height of the martian atmosphere?
iii)Why is this the maximum height and not the real height?

I got for i)1.9x 10^7m/hr
ii) 1.9 x 10^6m

Answer 1

1. Vi = 5.4km/s * 1mi/1.6km * 3600s/h = 12,150 mi/h.

2. h = Vi*t + 0.5g*t^2.
g = 3/8 * 9.8 = 3.675 m/s^2
t = 6min * 60s/min = 360 s.

h = 5400*360 + 0.5*3.675*360^2 = 2.18*10^6 m., max.