Answers above seem to provide a complete and reasonable answer for your question.
Anyway, I will try to go deeper:
The verb and noun Strike have two distinct meanings:
- Strike (verb) - to hit someone/thing violently -
I will strike him until he tells me what is wrong.
- Strike (verb) - to stop an activity or work due to low salary, low working conditions or any other issue that might exceed one's working capacity -
Bus drivers will strike next week
- Strike (noun) - the act of hitting something/someone violently -
The strikes from her husband on her were very constant
- Strike (noun) - the act of stopping working due to salary, working conditions or any other issue that might exceed one's working capacity -
Truck drivers were on strike due to low salary
Notice how we use Strike as a verb and noun;
as a noun, it is always used with a preposition on, when expressing the act of stopping working.