A footballer kicks a ball at an angle of 45° with the horizontal. If the ball was in air for 10 seconds and lands 4000meters away. Determine the initial speed

Answer 1

Angle of Projection = 45°

Horiontal distance covered by Ball(R) = 4000 m

Time in air = 10 s

R = u² sin 2θ /g where u = Initial Speed, g = Speed of gravity = 10

4000 = u² sin 90 / 10

∴ u² = 40000

∴ u = 200m/s

Answer 2

horizontal distance=V*cos45*time
V=4000/10*cos45=400*1.4=560 m/s a speeding bullet?
4000m is a long way in 10 sec. at 60miles/hr, that is 88ft/sec=about30m/sec