# One Dimensional Kinematics Question

• May 7th 2012, 02:44 PM
Serin
One Dimensional Kinematics Question
Hello all, first post so I'll try to be as clear as possible. I'm doing some revision for a University exam, and I have been trying to learn about trigonometry and some complementry equations for Vector explaination in 2D.

I've managed to figure out the trig suff so I have the tools but not the knowledge to figure the rest out. Here is my question:

A Dinosaur is running scared as Meteors fall onto the Earths surface, at a given point his life becomes in peril as one Meteor looms over head and may well be set to directly collide with our fearful lizard friend.

- The Dinosaur is travelling at a constant velocity of "X"km/h.
- The Meteor is travelling at an initial velocity of 100km/h and is accelerating at 2km/h2.
- As it happens we know where the meteor hits and sadly the Dinosaur is struck after having travelled 200km. (yes I know the distance is rather unbelievable)
- The Meteor started directly above our x-dino friend stationed 200km above it, before hitting the dinosaur, trigonometry says that the meteor had travelled 282.885km.

Here are the questions;
- how long did it take the meteor to travel 282.885km?
- and using that time how fast was the dinosaur going to have been so unlucky?

The difficulty comes from the meteor not just having a velocity but also acceleration.
• May 7th 2012, 02:56 PM
skeeter
Re: One Dimensional Kinematics Question
standard kinematics equation with constant acceleration ...

$\displaystyle \Delta x = v_0t + \frac{1}{2}at^2$

$\displaystyle \Delta x = 282.885 \, km$ , $\displaystyle v_0 = 100 \, km/hr$ , $\displaystyle a = 2 \, km/hr^2$

$\displaystyle 282.885 = 100t + t^2$

$\displaystyle t^2 + 100t - 282.885 = 0$

use the quadratic formula to solve for t in hours ... calculate the dino's speed using your calculated time and the distance it traveled.
• May 8th 2012, 03:09 AM
Serin
Re: One Dimensional Kinematics Question
Why thank you very much, that was very clear.