Amortization for the period is 3,644. So its Acc.Amtzn credit and Amtz. Expense Debit. 2 Amtz.on moving truck 500. So its Amtz. Moving truck Debit and Acc Amtz. Moving truck Credit.What is the difference between the two questions why is one a expense and the second question is not.Please help me understand the difference between the two questions, Thanks

The amortisation of the truck is only a part of the total amortisation expense

A truck would not have amortization. It will be Depreciation. Amortization would be used on Intangible Assets.

You will have 2 different journal entries:
Debit Amortization Expense for 3,644
Credit Appropriate Intangible Asset for 3,644

Debit Depreciation Expense for 500
Credit Accumulated Depriation - moving truck for 500