Answer: The Union Army was motivated to attack a second time in the battle of Chickamauga to defeat the Confederate Army and gain control of the strategic location.
Long Answer: The Union Army was motivated to attack a second time in the battle of Chickamauga because they believed that they had the superior military force and strategy, and that a second attack would give them an opportunity to defeat the Confederate Army and gain control of the strategic location. Additionally, the Union Army was under pressure to achieve a victory and make gains in the war, and an attack at Chickamauga presented a good opportunity to do so. Furthermore, the Union Army had received reinforcements and were confident that they could overcome the Confederate Army and emerge victorious in the battle.