None us wants to see our children hurt, but if we don't set limits then children will have a difficult time coping later in life.
Your job isn't to make them like what you are asking them to do (i.e. homework) it's to encourage her/him to take responsibility and do the right thing.
This might be to discontinue television viewing, or playing until it is accomplished.
If you rescue children from anger at your boundary, you can plan on more anger at a later date.
One child had a tantrum every time a soft ball game didn't go his way. He stormed off and then came back later, disrupting the team. The parent who was coaching the team, told the child if he left the field, he could not come back in the middle of the game (he talked to the child's parents and they agreed). This happened several times and he was not allowed to join in. He finally accepted that in order to play with the others, he had to stay and not storm off in a tantrum.
If an older child (around 12) refuses to get ready for a family outing. Explain that you will have to hire a babysitter to take care of him while the rest of the family go. Let him know the payment for the babysitter will come out of his money.
If a child won't get ready for school and misses the bus and you have to take time off work to take them, don't drop them at the gate, let them walk the last mile or so to get to school.
Most of all:
Be consistent
Be clear about consequences
Follow through with the consequences
