So i was in this suv with my buddy the other day and we came to a red light on a downward slope. He used his hand brake to stop sliding and somehow we got into a debate about something and i put 50 bucks into a bet. Here it is : -Assume we have 2 identical cars -The car weights 1 ton itself -1 of the car is carrying 1 ton of stock so it weights 2 ton -We assume the stock has the same centre of gravity as the car. -We put the 2 cars side by side on a flat road and slowly raise a downward slope -Which car will start sliding down first? I'm betting on both car slide at the same time and same speed because the weight is proportional to the force of gravity and the extra force balances out with the extra friction on the wheel and road. My buddy thinks the heavier car requires a bigger initial force to start sliding so the 1 ton car will go first.