A football is punted from the ground, it passes through the apex of its flight, and it begins its downward decent, as shown. When its height above the field is h=2.8m, the horizontal and vertical components of its velocity are observed to have the values vhorizontal=18m/s and vvertical=1.25m/s, respectively.

Question

A football is punted from the ground, it passes through the apex of its flight, and it begins its downward decent, as shown. When its height above the field is h=2.8m, the horizontal and vertical components of its velocity are observed to have the values vhorizontal=18m/s and vvertical=1.25m/s, respectively.

Determine the magnitude of the horizontal component of the football’s initial velocity v0,x, in terms of vhorizontal, vvertical, g, and h.

Calculate the time, in seconds, from when the football left the ground until it is descending at a height of h=2.8m.

Answer 1

v0,x = √(vhorizontal^2 + vvertical^2) = 18.6 m/s

Time = (2h/g) + (vvertical/g) = 2.2 s