My nephew's mom who is divorced from my brother disciplines freely, and in anger. I think this is wrong. I am not wholly against beating a child if there is a compelling reason, but it needs to be done without anger and either needs to be to protect the child or as a last resort when all other forms of discipline have failed.
In the case of protecting the child, I mentioned if a child tries to run out into the street, or play with pots on the stove, or drink bleach, or do some other dangerous act it is better to instantly deliver pain to a child than to have them become horribly disfigured, crippled, killed sick, and such. Discipline in this case is purely to protect the child from far more serious harm, this is a very appropriate case for such punishment, and should be a first resort.
If there is no such clear danger involved it should be a last resort, after many other things are tried, such as time outs, restrictions, lectures, and such. In general you want a child to behave well not because they fear being punished for behaving badly, but because they see a benefit in behaving well. The key thing is is love, there must be love and respect shown for children always, even when they do wrong and when they are being punished.
This is why violence against children done in anger can never be a solution to a behavioral problem, and it also has the negative effect of showing them that it is okay to react with violence when you are angry. A very bad idea.