For a class expierement we went outside and watched an air rocket launch into the air, and measured the total hang time.(adsbygoogle = window.adsbygoogle || []).push({});

Only knowing the time, find the velcotiy at liftoff.

the time is 7 seconds, and i understand that at the maximun height the time is 3.5 seconds. I dont know which equation to use becuase i am not familar with knowing only one variable.

we have 4 equations to choos from.

D = v*t

Vf = Vi + a*t

D = Vi*t + 1/2 a * t

Vf squared = Vi squared +2*a*d

Can you help me ?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Kinematics of rocket - calculate total hang time

**Physics Forums | Science Articles, Homework Help, Discussion**