Home | Community | Message Board

Avalon Magic Plants
Please support our sponsors.

Community >> The Pub

Welcome to the Shroomery Message Board! You are experiencing a small sample of what the site has to offer. Please login or register to post messages and view our exclusive members-only content. You'll gain access to additional forums, file attachments, board customizations, encrypted private messages, and much more!

Jump to first unread post. Pages: 1
Crazy Mofo
Male User Gallery

Folding@home Statistics
Registered: 06/17/02
Posts: 9,102
Loc: In A Forest Of Colossal F...
Last seen: 9 months, 29 days
physics anyone?
    #7578162 - 10/30/07 09:34 PM (13 years, 4 months ago)

A rocket is launched at an angle of 57.0° above the horizontal with an initial speed of 98 m/s. It moves for 3.00 s along its initial line of motion with an acceleration of 30.0 m/s2. At this time its engines fail and the rocket proceeds to move as a free body.

(a) Find the maximum altitude reached by the rocket.

(b) Find its total time of flight.

(c) Find its horizontal range.

On a mission to prove that the truth gets you no where.
They tried the truth, It didn't work. Then they wrote the bible. 

Only the foolish fear the inevitable.

Post Extras: Filter  Print Post  Remind Me! Notify Moderator
I'm a teapot User Gallery

Registered: 06/11/06
Posts: 516
Loc: Europe
Re: physics anyone? [Re: Phychotron]
    #7578288 - 10/30/07 10:20 PM (13 years, 4 months ago)

Thinking the problem without the acceleration of 30 m/s² in the line of motion first (which is a straight line from the start point of the rocket with a 57° angle with x-axis) and you have the equation for the movement relative to the y-axis:
y (relative to the y-axis) = 98*sen(57°)*t - 0.5*9.8*t²

If you had an acceleration of 30 m/s² along the initial line of motion, well, the initial line of motion is the line passing through the origin of the launch and 57° with the x-axis, but you're interested in the movie along relative to the y-axis, so you decompose the acceleration in the x and y axis, therefore,
a_x = 30*cos(57) ~ 16.34 m/s²
a_y = 30*sin(57) ~ 25.16 m/s²

Now you can use the acceleration in the y-axis,
You have ~25.16 m/s² up, and g ~ 9.8 m/s² down, then you have 15.36 m/s² up for 3 seconds, therefore,

y(t) = 98*sen(57°)*t + 0.5*15.36*t² = 82.19*t + 7.68*t²

The only acceleration in the x-axis direction is the a_x, then,
x(t) = 98*cos(57°)*t + 0.5*16.34*t² = 53.37*t + 8.17*t²

OK, you have the equation for the y-axis and x-axis before the engine failure, now you see the movement of the rocket before the engine failure,

Since the rocket moved this way for 3 seconds, you use t = 3 to find the altitude reach by the rocket before the engine failure:

y(3) = 82.19*3 + 7.68*3² = 246.57 + 69.12 = 315.69m

The distance traveled in the x-axis is:
x(3) = 53.37*t + 8.17*t² = 233.64m

Now when the engine turns off you have the normal projectile movement for the rocket with just - g ~ - 9.8m/s² in the direction of y and no acceleration in the direction of x, you can continue from here using y(3) and x(3) as the starting position, with that same angle for this movement and you'll find the maximum altitude.

I hope it helps, but I'm really not sure if it's right :smile: maybe I forgot something...

Edited by shroower (10/30/07 10:22 PM)

Post Extras: Filter  Print Post  Remind Me! Notify Moderator

Registered: 10/19/06
Posts: 242
Last seen: 10 years, 1 month
Re: physics anyone? [Re: Phychotron]
    #7578320 - 10/30/07 10:30 PM (13 years, 4 months ago)

for highschool projectile motion stuff just break it into 2 parts (going up and coming down) and its pretty straight forward.

Post Extras: Filter  Print Post  Remind Me! Notify Moderator
Not here
Male User Gallery

Registered: 06/25/01
Posts: 16,503
Loc: Longitudinal Center of Ca...
Re: physics anyone? [Re: Phychotron]
    #7578372 - 10/30/07 10:50 PM (13 years, 4 months ago)

*scoffs at basic kinematics problem*


Welcome evermore to gods and men is the self-helping man.  For him all doors are flung wide: him all tongues greet, all honors crown, all eyes follow with desire.  Our love goes out to him and embraces him, because he did not need it.

~ R.W. Emerson, "Self-Reliance"


Post Extras: Filter  Print Post  Remind Me! Notify Moderator

Registered: 12/11/03
Posts: 29,258
Re: physics anyone? [Re: WhiskeyClone]
    #7578374 - 10/30/07 10:51 PM (13 years, 4 months ago)


WhiskeyClone said:
*scoffs at basic kinematics problem*


:lol:  same here.  I just got off of work tutoring that shit for 5 hours.  Go to physicsforums.com  they are pretty good about answering questions.

Post Extras: Filter  Print Post  Remind Me! Notify Moderator
Jump to top. Pages: 1

Community >> The Pub

Similar ThreadsPosterViewsRepliesLast post
* Does this mean im physically addicted to alcohol?
( 1 2 all )
NOUS333 464 35 04/20/18 10:41 AM
by Amanita86
* COINTELPRO Redux: Global Order Targets the 9/11 Truth and Patriot Movements Visionary Tools 988 1 11/04/07 11:40 AM
by WScott
* The New years Banning Resistance Movement... beejay 1,011 14 12/31/04 12:57 PM
by MeatSpace
* quantum physics.....
( 1 2 all )
mikeytro 4,398 37 04/12/07 04:53 PM
by Ego Death
* Basic physics help
( 1 2 all )
Gumby 2,181 22 10/03/06 04:06 AM
by Konnrade
* for those that appreciate controlled rythmic movements.. Yoschie99 567 6 06/02/06 08:43 PM
by Simisu
* Need To Know! Non DOT drug test/Physical Helge 9,499 4 06/01/06 12:22 AM
by Helge
* The physics of physics GreenScreen 1,062 14 06/07/07 08:26 AM
by trendal

Extra information
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Entire Staff
465 topic views. 8 members, 18 guests and 30 web crawlers are browsing this forum.
[ Print Topic ]
Search this thread:
Please support our sponsors.

Copyright 1997-2021 Mind Media. Some rights reserved.

Generated in 0.04 seconds spending 0.01 seconds on 16 queries.