Chiếu tia sáng vuông góc với bề mặt gương. Tính góc tới và góc phản xạ

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

How many atoms of nitrogen are in the chemical formula ni(w on

The items in the following list are all units of matter. which is the smallest unit that retains the properties of the matter? a.) atom b.) compound c.) electron d.) element