How do I calculate the acceleration of a moving container on a specular surface?

[Facelam]

Homework Statement

It's open container with water which moves horizontally. It moves with some acceleration. Angle of incidence (α) and angle of reflection(β) on water are given (α=40 deg., β=20 deg.). We need to find container's acceleration.

Homework Equations

a=(v2-v1)/t (?)

The Attempt at a Solution

I've built angles of incidence and angles of reflection for both cases when v=0 and a=0 but what do to further is a big question for me (maybe this way of solution is wrong).

I'll be grateful for the help

 

[haruspex]

Is this your own diagram or was it provided?
Have you stated the question, word for word, as it was given to you?
I ask because it would be unusual for a horizontally accelerating body of water to have a horizontal surface.

 

[Facelam]

Is this your own diagram or was it provided?
Have you stated the question, word for word, as it was given to you?
I ask because it would be unusual for a horizontally accelerating body of water to have a horizontal surface.

It's open container with water on car. Diagram was provided without vector a

 

[haruspex]

It's open container with water on car. Diagram was provided without vector a

Ok. Distrust the diagram.
Consider a small parcel of water on the surface, or maybe some particle floating there, just submerged. Draw a free body diagram for it. What forces are there? How do these forces account for the acceleration?
Alternatively, if you are comfortable with non-inertial frames, in the frame of reference of the car what are the forces?

 

[Facelam]

Ok. Distrust the diagram.
Consider a small parcel of water on the surface, or maybe some particle floating there, just submerged. Draw a free body diagram for it. What forces are there? How do these forces account for the acceleration?
Alternatively, if you are comfortable with non-inertial frames, in the frame of reference of the car what are the forces?

It's a copy of diagram and it moves horizontally

 

[haruspex]

It's a copy of diagram

this diagram shows the container, not the water surface. Note that the incident and reflected rays are not shown meeting.
In your original diagram you assumed acceleration was to the left.

 

[Facelam]

this diagram shows the container, not the water surface. Note that the incident and reflected rays are not shown meeting.
In your original diagram you assumed acceleration was to the left.

There is water inside that container. Yeah, and I can't understand why (how is it possible?).
Acceleration to the left is my supposition

 

[haruspex]

There is water inside that container. Yeah, and I can't understand why (how is it possible?).
Acceleration to the left is my supposition

Yes, there is water inside, but the diagram does not show it, so you do not know what the surface looks like.
Please try to answer my questions in post #4.

 

[Facelam]

Yes, there is water inside, but the diagram does not show it, so you do not know what the surface looks like.
Please try to answer my questions in post #4.

Don't understand why I didn't see it

 

[haruspex]

Don't understand why I didn't see it

That looks much better.

 

[Facelam]

That looks much better.

Thank you for help!