Aball is launched from the ground with a horizontal speed of 30 m/s and a vertical speed of 30 m/s. what is the ball's horizontal acceleration at the top of its trajectory?

the horizontal acceleration of the ball at the top of the trajectory is zero.

in case of projectile motion,only the force of gravity acts on the object along the vertical. There are no horizontal forces acting on the object.

now force = m a

m= mass

a= horizontal acceleration

f= horizontal force=0

so a= F/m

a=0/m=0

so the horizontal acceleration at all the points including the top of the trajectory is zero.