Final answer:
The MIPS assembly instruction to load a word from a specific memory address into a register is 'lw $8, 60($10)', where $10 contains the base address 0x00400000 and the word is at 0x00400060.
Step-by-step explanation:
The instruction to load the word at address 0x00400060 into register $8, given that register $10 contains 0x00400000, can be achieved using the lw (load word) instruction in MIPS assembly language. The address from which the word is to be loaded is 60 hexadecimal units away from the address stored in $10. The corresponding MIPS instruction takes the form:
lw $8, 60($10)
This instruction works by adding the immediate value 60 to the content of register $10 and then loading the word from the resulting memory address into register $8.