A machine that produces cellphone components is purchased on January 1,2020 , for $168,000. It is expected to have a useful life of four years and a residual value of $14,000. The machine is expected to produce a total of 200,000 components during its life, distributed as follows: 40,000 in 2020,50,000 in 2021,60,000 in 2022 , and 50,000 in 2023 . The company has a December 31 year end. (a) Calculate the amount of depreciation to be charged each year, using each of the following methods: i. Straight-line method Straight-line method depreciation \$ per year