# Motion of projectiles

• Jul 29th 2012, 09:29 PM
srirahulan
Motion of projectiles
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?
• Jul 29th 2012, 10:51 PM
earboth
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 $\displaystyle v = 22\ \frac ms$