Compare the vf calculated at the point of impact to the horizontal velocity you calculated using δx and δy. were the vf and the projectile velocity equal? if not what contributed to the difference? think about the collision.

Velocities are not equal

Explanation: A projectile usually have a given initial velocity, the velocity must be resolve into components of x and y with respect to the velocity of the projectile in a certain angle. In a projectile trajectory the final velocity for the y- component is always 0m/s since the object reaches its maximum point.

temp rises, and expansion