gravity

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Permalink Reply by Daniel Piker on February 9, 2017 at 6:05am

In your definition you were applying the same force to both objects, not the same acceleration.

The gravitational force is given by m*g, where m is mass and g is acceleration due to gravity. So you would need to include this multiplier in your force calculation.

Now force = mass*acceleration, or F=ma(Newton's second law) can be rearranged to a=F/m (and indeed this is what Kangaroo uses in the solver).

So for the acceleration of each particle we have

a = (m*g)/m

and the mass cancels out.

Note that you also need to set drag to 0, since it will affect bodies of different mass differently - it is a force opposed to and proportional to the velocity (an approximation of air resistance). A more massive body will therefore be slowed down less than a light one.

Changing these inputs it gives the correct result of both bodies falling at the same rate.

 

Attachments:

• gravity.gh, 14 KB

Permalink Reply by nachop on February 9, 2017 at 1:43pm

Thanks a lot, does the DRAG parameter affects differentenly depending on ojects shape or just depending on the mass

Permalink Reply by Daniel Piker on February 9, 2017 at 4:05pm

The effect of drag depends only on the mass and velocity of the particle.