There are certain issues when it comes to copyright as it is quite a tricky subject. You are aloud to use peoples objects as long as you don't try and make prophets from your product. Also if big companies have bought into all their products you cannot use a clip for more then a couple of seconds otherwise it is illegal. Also if you are portraying a bad message about that company than it is illegal to use any of their products to do that.
Also we learnt about intellectual property rights. This is when someone makes a product or uses somebody Else's work, the client (which is either you or someone else) has to either buy it straight out which means the person who made the product gets one large amount of money at once or pay gradually which means person who made the product gets a percentage each time that product sells.
I learnt how to use these rules in my Project which is all graphic design work. I learnt that to use the college logo we have to make it a certain size and that I'm not allowed to use other peoples pictures unless I asked them or bought it, but I took all the pictures I used myself.