Question

A lunar landing module is descending to the moon’s surface at a steady velocity of 10 m/s. At a height of 120 m, a small object falls from its landing gear. Taking the moon’s gravitational acceleration as 1.6 m/s^2 , at what speed, in m/s does the object strike the moon?

Answer 1

$\text{let us throw the material point up}$

$h_{max}=\frac{V_0^2}{2a}$

$V_0 =\sqrt{h_{max}*2*a}=\sqrt{120*2*1.6}\approx19.6$

$\text{Upon reaching the surface, the body has the same speed}$

$\text{Add lander speed and get the answer } V=10+19.6 =29.6$

Answer:  $V=29.6\frac{m}{s}$