You may infringe copyright when copying and pasting others’ resources into your own webpage. Look for those that are open source or under creative commons licence!
All you need to do is to attribute to the content owner and make sure you don’t sell the material.
The following are open source:
For GREAT physics animations: http://bq.bqlearning.org/physlet/index.html
For a COOL 363 pg physics textbook from a reputable university professor: https://www.physics.upenn.edu/sites/www.physics.upenn.edu/files/Classical_Mechanics_a_Critical_Introduction_0.pdf