A football punter wants to kick the ball so that it is in th

A football punter wants to kick the ball so that it is in the air for 4.0 s and lands 50 m from where it was kicked. At what angle and with what initial speed should the ball be kicked Assume that the ball leaves 1.0 m above the ground.

Solution

the horizontal distance is,

x = u_xt

50 = ucos@*4

u*cos@ =12.5

the vertical displacement is,

y = u sin@ t+0.5 a t^2

-1.0= u sin@* 4 - 0.5*9.8*4²

u sin@ =19.35

use the above two equations to determine the angle.

tan@ = 19.35 / 12.5

hence, the angle is, @ = 57.13^o

B.

use the below equation to find the speed.

u sin@ = 19.35

then, the speed is, u = 23.03 m/s