What was the reason that the Confederate army burned Richmond?

Burned District in Richmond. In the midst of evacuating Richmond to Union forces on April 3, 1865, Confederate soldiers set fire to tobacco warehouses and the conflagration spread throughout the commercial heart of the city, leaving nine-tenths of the business district in ruins.

1.02m

Explanation:

Apply Principle of conversation of energy,

mgh = 1/2 Ke²