# Roll over of a car

1. Nov 10, 2009

### varunsangani

Will a car roll over if there is a change in centre of gravity?

2. Nov 10, 2009

### stewartcs

Possibly. Depends on how much of a change and where it occurred.

CS

Last edited: Nov 10, 2009
3. Nov 10, 2009

### Ranger Mike

probably so
imagine a pick up truck with load of steel I beams, stacked above the pick up bed..this changes the center of gravity height AND possibly the center line location from the Roll Centers front and rear...does it not?
.now imagine what happens when the truck makes a sharp right turn and the tie straps used to secure the I beams suddenly breaks..the weight shifts to one side ( as does the center of gravity height and location from the vehicle center line...as does the distance from the vehicles Roll centers and makes for a much longer lever to act about the RC..this could bottom out the springs on that side of the truck and by doing this..effectively do away with any form of working suspension and now we have an overloaded Go Cart not able to handle the sprung weight and the result is lifting the wheels on the opposite ..given enuff speed and sharp enuff cornering...hang on and hope your are belted in ..tight..

4. Nov 10, 2009

### Brian_C

Sounds like a good Matlab project.

5. Nov 10, 2009

### Mech_Engineer

It all depends on how the center of gravity changes, and what the car is doing at the time. If the CG gets higher in a flat high speed turn, the car might roll over; but if the CG gets lower or moves towards the center of the curve, it's doubtful the car will roll. if the car is stationary, it will only roll over if the CG moves outside the box defined by it's 4 wheels.

Are you trying to manipulate a car's CG?

6. Nov 10, 2009

### tiny-tim

Hi varunsangani!

When a car accelerates (relative to the road), the equivalence principle means that an observer in the car can regard the car as stationary, provided he regards there as being an equal fictional gravitational acceleration.

Add that horizontal fictional gravitational acceleration to the vertical real gravitational acceleration, g, to get a total effective acceleration on the "stationary" car.

The direction of that will not be vertical, and the car will roll over if the line in that direction, from the centre of mass, goes outside the wheelbase. The higher the centre of mass, the further that line will go.