At the maximum height of a projectile, the velocity and acceleration are

At the highest point of a projectile the velocity and acceleration are perpendicular to each other Angle between $\overrightarrow{a}\text{\hspace{0.17em}and\hspace{0.17em}}\overrightarrow{v}\text{\hspace{0.17em}is\hspace{0.17em}}90°$