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What else can I help you with?
Is Poland self-sufficienct or does it depend on international trade?
Poland is a member of the European Union and is dependent on trade.
What helps bridges support weight?
weight is misunderstood by some people. weight is defined as; mass x gravity, but, mass is not weight, and gravity is an accelerating force which pulls every mass towards the earth surface, which if there were no normal reaction force from the ground, each person standing on it would sink into it. Bridges react to the accelerating forces imposed upon them, so if a car was parked on a bridge, a reaction force would be set up from the bridge to counteract the accelerating force from the car on the road surface. Weight is really a balance of energy, therefore; mgh = KEV^2. If you pick up a shopping bag with lots of food stuff in, you say it is heavy, but what it is really, is energy, your energy mgh, against KEV^2, when the energy in the bag is greater than your energy, like picking up a concrete block, then you will not have sufficienct energy to pick it up? The bridge works in the same way, the energy the bridge has is significantly greater than any mass allowed to pass over it, or park on it.
