2D Elastic Collision Between Billiard Balls

Physics Ninja looks at 2 dimension elastic collision between billiard balls of the same mass. Conservation of momentum and conservation of kinetic energy are used to obtain a relationship between the angles after the collision.

[kina]

You remind me of what Prof Paul Dirac once said. He stressed the beauty of mathe and the importance of being able to predict the behaviour of an equation rather than just able to solve it. Your tenacity in working out a generalised form of an equation for intuition certainly satisfy the intellectual starvation of mathe and physics lovers like me. Thank you, please keep up your good work.

[weiv]

omg thank you you are the best teacher ever and this explanation was so helpful !!! :DDD

[aadarshoraonkg]

That's quite helpful with all my doubts cleared please please make a video on loss of K.E during 1dimension non elastic collision

[nickclute]

this didn't work on my homework and I am shook. It made so much sense and all for it to not work.

[jurrich]

This seems to lack transfer of rotation, which is quite annoying since everyone seems to omit this, even though it's a crucial part of programming billiards/pool/snooker collisions.

[abdallahabughazaleh]

Thank you so much, you really explained it perfectly

[TheOldeCrowe]

Your equation (3') tells you that v1f and v2f are two legs of a right triangle with hypotenuse v1i, which immediately gives you φ + θ = 90°. The extra algebraic manipulation, while not strictly necessary, was still instructive though. Enjoyed your video.

[soumyodeephalder]

I like the way you teach its very engaging. Thank you

[justinabissett]

So I'm studying for a physics exam, and a similar problem came up where it's an elastic collision with two billiard balls. Ball one moves with an initial velocity of 3m/s, and after collision with ball two, ball one travels 30 degrees to the x axis, where ball two travels 14.5 degrees below the x axis. I went through this whole video, as it was the closest thing I could find on how to solve a problem like this, and at the end noticed 30 and 14.5 do not add up to 90. Now I'm even more confused and have no idea how to solve for the final velocities. I've tried every method I can think of, and nothing works. Could you steer me in the right direction? I've spent over an hour on just this problem alone. Any help would be appreciated, thanks.

[michaelgarcia]

Based on the initial condition, you have a direct central impact which implies both ball velocities after the collision will be along this central line (x-axis) after the collision. You are calculating an “oblique impact” which implies you need to know the “off-axis angle” of the incident ball and resolve its components before the collision which you are not specifying.

[wilsonsikazwe]

We need more questions on collisions sir

[pgille]

I don't understand why you can add equations 1'' and 2'' together. Can you explain this please? Thanks

[crabby]

This is so counter intuitive, what if one of the angles is 1? Then the other is 89? Right? But if it's 0 then it just bounces back?

[AliyaIdris-bitf]

Hi! This question is driving me nuts!😥 Pls help! Two identical frictionless balls moving upward strike each other. If ball A is moving to the right with velocity 30fts^1 and making an angle of 30⁰ with the normal axis and ball B is moving to the left at a velocity of 40fts^s making an angle of 60⁰ with the normal axis. Assume e=0.9. Calculate the magnitude of the tangential and the normal velocoty component of ball B

[michaelrogers]

I'm working on a similar problem that reads
Two identical billiard balls are on a frictionless, horizontal surface. Ball 1 has an initial velocity of 5.00 m/s in the positive x direction, and ball 2 is initially at rest. The balls collide, and, after the collision, ball 1 is moving at a speed of 2.00 m/s at an angle of ϕ=
30.0° below the positive x axis, as shown in the diagram.
What angle θ, in degrees, does the final velocity of ball 2 make with the x axis?
What is the speed, in meters per second, of ball 2 after the collision?
The final answer for the first part was 17.01 degrees which contradicts the point made at the end of the video

[hoanguyentrung]

It's the same that you made a cue ball radial shot. What happens in the opposite case?

[andrewombun-ttfv]

What are some examples of center of gravity?

[lovelyibrahim]

i want you teach me physics so that i will understand every content of physics

[akinrinbolaopeyemi]

A 20kg body traveling east at 20m/s collides elastically with a 10kg body moving west at 2m/s. After the collision, the lighter body is scattered in a direction of 30°south of East. Calculate the speeds of the two bodies after collision and the direction of the heavier body

[whyshouldi]

This doesn’t help me as I am not given either of the angles to start with. I’m given the means to solve for the final velocity of the ball that was hit using energy.