Projectile Motion_MCQ 1

Which of the following is a TRUE statement regarding the motion of projectiles? Neglect air resistance. SELECT ALL THAT APPLY!!!
The velocity of projectiles is smallest at the apex of the trajectory.
All projectiles have zero velocity at the apex of the trajectory.
The acceleration of the projectiles is greatest at the apex of the trajectory.
The projectiles’ velocity is zero (0 m/s) at the apex.
The velocity and acceleration vectors are perpendicular at the apex.

A cannonball is fired with an initial velocity of 20 m/s and a launch angle of 45o at a wall 30 m away. If the cannonball just barely clears the wall, what is the maximum height of the wall?
5.92 m
6.34 m
7.51 m
7.96 m
8.32 m

The diagram below shows the path for a projectile where points B and J are at the same height. If we compare the directions for the horizontal velocity (vx), vertical velocity (vy), and the resultant velocity (v) at points B and J, which velocity(ies) change direction?
vx only
vy only
vx and vy only
v only
vx and v only
vy and v only
All the velocities (vx, vy, and v) change direction.