Question

A tennis player serves a tennis ball such that it is moving horizontally when it leaves the racquet. When the ball travels a horizontal distance of 11m, it has dropped 50 cm from its original height when it left the racquet. What was the initial speed of the tennis ball? (Neglect air resistance.)

Answer 1

Easy: as we neglect the air resistance we have an motion in x and y where y is the height and x the distance: This is an motion that we can thread like 2 independent ones: where 0.5=9.81*t^2/2 or t=0,32 seconds so the ball has flewn 11 meters in 0.32 secs or 34 m/s.

Answer 2

As the ball leaves horizontally it doesnt have an begin speed in y-orientation

Answer 3

Thanks so much!