# Will cars with different mass make a loop in a tunnel with same given velocity?

1. Oct 27, 2014

me and my colleague watched Mercedes Benz commercial where its sports car accelerated, went in a tunnel, and made a complete loop around the tunnel by going up against the wall. Now, the debate was on whether a car can manage to make a loop in a same tunnel with same given velocity entering the loop, no acceleration once the car enters the loop, and manage to make a loop with heavier car (say, Ford F-150).
With conservation of energy, it has same mass, gravity, and velocity, it must reach same height. But I think once the car hits 1/4 of the loop, centripetal force pulling down the car is greater so with same velocity Mercedes can make the loop, Ford F-150 may not.
What do you guys think?

2. Oct 27, 2014

### Staff: Mentor

"centripetal force pulling down the car"? That does not make sense.
Anyway, centripetal force will be larger, but so will the mass that resists velocity changes. All forces scale in the same way.

Imagine a heavier car as two lighter cars directly behind each other. Or even a single car as composed of many different parts. Why should this behave differently?