In 2 dimensional kinematics, why is there acceleration in the vertical direction but not horizontal?

In 2 dimensional kinematics, why is there acceleration in the vertical direction but not horizontal?

Correct answer: D. Gravity (an acceleration) only acts in the vertical direction. It slows an object on the way up and speeds the object up on the way down. Horizontally speaking there is nothing “pushing” the object forward, just it continues moving with the same initial horizontal velocity it left the ground at.

Verified by Knowlaxy Team (Jason Kuma)