What's frame per sec in spritesheet animation in unity3d 4.3?

Question 1

Sprite sheet animation in Unity 4.3 is just that, an animation. Which means you can control it.

An excellent tutorial on this subject is this one by Michael H.C. Cummings.

Once you have created your animation (by dragging the frames of your animation into your scene), you might find that your animation is playing far too fast. I believe the default is 60 frames per second. That doesn't mean you need to create your animation to contain 60 frames for each second. You can adjust this.

Go to the animator window for your animation and adjust the samples.

If the animation you've created consists of 12 frames per second, set it to 12. After that your animation should work just fine.

Note: In later versions the "Sample Rate" seems to have disappeared from the UI. Please see the other answer for how to adjust this now.

If you need something other than the preset choices offered, you can still edit the rate manually as well. Select your animation in the project, then in the inspector you can switch to "Debug" mode by clicking on the three vertical dots at the very top right of the inspector window. Select "Debug" instead of "Normal" and your sample rate should appear as a field with an integer value. You can now edit this to a value of your choice.

Question 2

Increase and decrease frame per second in unity 2D and 3D [2020.1]