Final answer:
It is not safe to cross the bridge with a 3500 kg vehicle since the bridge has a capacity limit of 3 tons (3000 kg), and the vehicle exceeds this limit by 500 kg.
Step-by-step explanation:
If a bridge can only accommodate a 3-ton vehicle at a time, and you are driving a 3500 kg vehicle, it is not safe for you to cross the bridge. A ton is equivalent to 1000 kg, so a 3-ton capacity means the bridge can support vehicles up to 3000 kg. Since your vehicle weighs 3500 kg, it exceeds this limit by 500 kg. Therefore, crossing the bridge with your vehicle would be unsafe and should not be attempted.