A jet plane is cruising at 210 m/s when suddenly the pilot turns the engines...

J

jskijessi

New member
...up to full throttle. After travel? A jet plane is cruising at 210 m/s when suddenly the pilot turns the engines up to full throttle. After traveling 2.0 km, the jet is moving with a speed of 240 m/s.
(a) What is the jet's acceleration, assuming it to be a constant acceleration?

i thought it would be 1.69 but thats not working
 
O

OldScienceGuy

New member
use this

Vf^2 = Vi^2 + 2 a d
240^2 = 210^2 + 2 a (2000) (must use meters)
solve for a
I get about 3.375 m/s/s
I wonder why your answer is half that.
 
T

tulip

Member
So from what I learned, it's best to list the givens first.

Givens: Initial Velocity (Vi) = 210 m/s
Final Velocity (Vf) = 240 m/s
Displacement (d) = 2.0 km or 2000 m

First, we know that Average Velocity = (Vf+Vi) / 2 AND average velocity = displacement / time.
We start by finding the average velocity = (240+210)/2, which should be 225 m/s
Therefore, 225 = 2000 / t. Multiply both sides by t and you get 225t = 2000, which makes t = 8.888888888888889

Now since we have t, we can solve for acceleration.
acceleration = (Vf - Vi) / t
(240 - 210) / 8.888888888888889 = 3.375

Your answer should be 3.375 m/s^2. I hope that's right!
 
Top