Finding Horizontal Displacement of a Dropped Cup on an Accelerating Airplane

  • Thread starter Thread starter nick227
  • Start date Start date
  • Tags Tags
    Airplane
nick227
Messages
35
Reaction score
0

Homework Statement


A cup of coffee is dropped aboard an airplane accelerating along a smooth runway. If it falls a vertical distance of 1.0 meter, find its horizontal displacement when it hits the floor. Assume a constant horizontal acceleration of 1.5m/s^2 for the airplane.


Homework Equations



F=ma

The Attempt at a Solution



This chapter is about noninertial reference systems, if that means anything for this problem.

I looked at the problem and said there was a force due to gravity and a force from the horizontal acceleration.

f=ma=mg+ma1

v(dv/dx)=g+a1

I don't think I started this correctly, because we don't have a velocity. Am I going in the right direction here?
 
Physics news on Phys.org
f=ma=mg+ma1
So suppose you have this. Now write a = dv/dt (I don't see how you managed to get v dv/dx) and integrate both sides.

Note however, that you should not just add the accelerations! They have different directions and therefore you should add them as vectors. Write out the acceleration in the horizontal and vertical direction separately. Then you can solve for the horizontal and vertical velocity and vector-add them to get the velocity vector. Or you can use just the horizontal velocity to find the horizontal displacement (you will need the other one as well though, since there will still be information missing you can only extract from the vertical component).
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top