Answer: 18.35 m/s
Step-by-step explanation:
At the highest point of trajectory, the vertical component of the velocity would be zero and the tennis ball would have horizontal component of velocity.
It is given that the initial velocity of the ball is 32 m/s and it makes 35° with the vertical. Hence the horizontal component of the velocity,
v sin θ = 32 m/s × sin 35° = 18.35 m/s
Hence, at the highest point in its trajectory, the tennis ball would be moving with the speed 18.35 m/s.