# What does multiplying the mass of an object by gravity do?

So I am looking at the jeep found in the suburban map, and I notice that in the “CarScript” it multiplies all of the cars “BaseParts” by gravity. What is the purpose of this?

In physics, multiplying a mass by an acceleration returns a force (according to Newton’s 2nd law). While Roblox physics do not emulate real world physics in many ways, body mover objects let us work with somewhat realistic forces.

The script uses a multiple value of the car’s weight to adjust its BodyPosition’s MaxForce X and Z coordinates. Higher values would suddenly move the car, while lower ones wouldn’t be enough for the desired effect.

The main purpose of the function that uses the weight is to keep the car balanced while 1) someone is driving it and 2) there’s something 3 studs under the chassis/car base. Then the suspension does the rest.

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How do you get the acceleration of a part?

Edit: Is the velocity of a part the same as the acceleration of a part?

Velocity is how the position changes depending on the time, while acceleration is how the velocity varies depending on the time. Both magnitudes are completely different!

Afaik, there is no property or function that gives you access to the acceleration of a BasePart. You could use some Heartbeat function to get a part’s velocity, substract its velocity from the last function call and divide the result by the elapsed time between both calls.

Note that all unanchored parts (and not welded to anchored parts) will experience a constant acceleration on the Y axis equal to `Workspace.Gravity` (`196.2 studs/second^2` by default).

I know this thread has been closed for quite a long time but can you pls explaint to me why do the mass is 4 times larger than the original mass of the entire car, like in the script, they times mass by 4 times
`force = mass * stats.Suspension.Value`