Constant speed can only be achieved in a universe with no other matter. So, you've got to remove friction(no air to bump into), gravity(no other mass pulling on the object to speed it up or slow it down), etc. It'll look very strange if those effects apply to every other...

c++,transformation,rigid-bodies

First of all, you need to represent any movement of AB as a rotation and translation about a single point, like point A for simplicity. Then, for any other point that needs to be rotated along with AB, you should move that point into the space of line AB by...

unity3d,unity3d-2dtools,rigid-bodies

Just change this: rigidbody.AddForce (5,5,0,ForceMode.Impulse); to 2D equivalent: rigidbody2D.AddForce(new Vector2(5, 5), ForceMode2D.Impulse); Also if you have 2D colliders attached to the gameObjects you need to use OnCollisionEnter2D instead of OnCollisionEnter PS. If you want just the force to affect to the speed remove this line: transform.Translate(speed * Time.deltaTime, 0, 0);...

You can set the parent of the child rigidbody to null in script: transform.parent = null; Reference: http://docs.unity3d.com/ScriptReference/Transform-parent.html...

Like Nick Udell already mentioned, your comparison of the tag is the source of your problem. All three balls are executing the same script at nearly the same time. So if you click on of the balls, all three scripts will cast a ray at your mouse position and check...

rotation is form of kinetic energy first the analogy to movement alpha - angular position [rad] omega - angular speed [rad/s] epsilon - angular acceleration [rad/s^2] alpha(t)/(dt^2)=omega(t)/dt=epsilon(t) now the inertia I - quadratic rotation mass inertia [kg.m^2] m - mass [kg] M - torque [N.m] and some equations to be...