How to calculate acceleration

Game Engine Game Engine Support and Discussion
1

I’m trying to get the acceleration of a given object at a given moment in time.
Does anyone have any tips on how to do this?
Is there a property, or would I have to calculate it from velocity?

Thanks.

2

Acceleration can be found from the net force being applied to the object and its mass (F=MA, or A = F/M). If you don’t have any friction or anything like that and you’re applying a constant force, you can find the force using those equations.

To calculate acceleration, you need 2 points in time very close to each other. You can use the velocities at those positions in combination with those 2 times to calculate the change in velocity, otherwise known as acceleration.

The equation for this would be (V1 - V0)/(T1-T0) where V1/V0 is the “current” velocity and velocity of the previous frame and T1/T0 are the current time and the time of the last frame. This would definitely require python.

If you don’t mind me asking, why are you looking for acceleration?

-Sam

3

Thanks for that.

Is there a property for the current force being applied to the object?

I’m writing some code that ‘observes’ how an object moves over time.

4

I made a quick example file. I don’t know if there’s a better way to get the “old” frame’s velocity and time, but what I have here works.

You’ll see that changing friction and damping will change the uniformity of acceleration. Currently, with damping and friction set to 0, and mass set to 1, it sees an acceleration of 10, which is the number set for the force accelerator (10 = 1 * A, A = 10).

Hope that helps!

Attachments

calculateaccel.blend (59.3 KB)

5

Yep, that is similar to what I’ve implemented.

Thanks again.

6

Long ago, my calculus teacher would have tried to make me understand that “acceleration is a second derivative.”

Velocity is the first-derivative: it is "the rate-of-change of ‘position.’ "

Acceleration, then, is the second derivative: it is "the rate-of-change of the first derivative, which is ‘velocity.’ " Or, “it is the rate-of-change of the rate-of-change of position.”

Acceleration will certainly require a bit o’ Python, but the equations are easy.