ABC Corp. purchased a delivery truck on January 1, 2021, for $50,000. The truck is expected to have a useful life of 5 years and no residual value. The company uses the straight-line method of depreciation. On December 31, 2021, the company decided to revise the estimated useful life of the truck to 6 years. What is the depreciation expense for the truck in 2021, both before and after the revision of the estimated useful life?