Can an employer force you to work past your scheduled time?

Yes, your employer can require you to work past your scheduled time. There are no specific laws that state you need to have significant notice before working additional hours, so there is nothing illegal about an employer having you stay at work for more hours that were not previously mentioned.

Now, you do have the option to either accept the additional work or deny it. If you do deny it, it is important to note that in most cases, it would be entirely legal for an employer to fire someone over a refusal to work additional hours. This employer right is protected under the Fair Labor Standards Act.