Re: Motion of projectiles

Quote:

Originally Posted by

**srirahulan** A lunar landing module is descending to the moon's surface at a steady velocity of 10ms^{-1}.At a height of 120m,a small object falls from its landing gear.Taking the moon's gravitational accleration as 1.6 ms^{-2},at what speed,in ms^{-1},does the object strike the moon?

1. Determine the time from the distance:

$\displaystyle d = v_0 \cdot t + \frac12 \cdot a \cdot t^2$

with $\displaystyle v_0 = 10\ \frac ms, ~ a = 1.6\ \frac m{s^2}, d = 120 \ m$

You should come out with t = 7.5 s

2. Use the value of the time to determine the final velocity:

$\displaystyle v = v_0 + a\cdot t$

You should come out with $\displaystyle v = 22\ \frac ms$