A physical firewall, router, modem. (if this is for a class then you might have to argue this point, a physical firewall is a piece of equipment but it is still software that does everything.)
A lock on the computer case.
.
yes
Physical components that make up your computer are known as hardware.
There are 2 physical components of a computer. Software and Hardware. For great example of each go to: http://www.slideshare.net/Amitchandra.5681/components-of-computer-2-presentation
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Hardware is something you can touch. So it is the physical components of the computer.
If your question is whether registry is physical in computer processor, the answer is no.
Hardware
All of them would be classified under "hardware" although the other devices connected to the computer would be classified in the subcategory "peripherals".
``hard ware``
A motherboard is the physical arrangement in a computer that contains computers basic circuitry and components.
a computer is a chemical change as it is a machine.