(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A rocket is launched at an angle of 53 degrees above the horizontal with an intial speed of 100 m/s. It moves along its initial line of motion with an accel. of 30 m/s^2 for 3 s. At this time its engines fail and the rocket proceeds to move as a free body. Find the maximum altitude reached by the rocket.

2. Relevant equations

Just the four basic kinematics equations. . ?

3. The attempt at a solution

I did:

where is the rocket when its engines fail?

d= vit + (1/2)at^2

= 100 sin 53 (3) + (1/2)(30)(3^2)

= 374.59 m

what is the rocket's speed after the engines fail?

vf= vi + at

=100 + 30 (3)

=190 m/s

So I feel like from here I should just be able to plug into vf^2= vi^2 + 2ad and find "d," using vi= 190 m/s and vf= 0. . . .But that's not the case. Why can't I do that? And where can I go from here? I have a feeling I need to find some way to express time to reach the maximum altitude, but I have no idea how I can express that.

~Thank you in advance!!

**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: Maximum altitude of a rocket launch

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