Simple answer: yes.
But, see this discussion on hobby income or business income. https://www.irs.gov/newsroom/hobby-or-business-irs-offers-tips-to-decide Schedule C is used for business income
Additional reference: https://www.thesimpledollar.com/make-money/is-your-business-just-a-hobby/
Hal_Al: Thanks for your reply. It does look like Sch C is the one to use. Could you please help with questions I asked in that post? I am not sure how well the IRS instructions would deal with them. Thanks.