A golfer wants to drive a ball a distance of 310 yards. If the 4-‐wood launches the ball at an angle at 15° above the horizontal, and assuming that the drive is over level ground (i.e. the start and final vertical position is the same; vertical displacement is zero), what must be the initial speed of the ball to achieve the required distance (assume a perfectly straight drive).

Question

A  golfer  wants  to  drive  a  ball  a  distance  of  310  yards.    If  the  4-­‐wood  launches  the  ball  at  an  angle  at  15°   above  the  horizontal,  and  assuming  that  the  drive  is  over  level  ground  (i.e.  the  start  and  final  vertical   position  is  the  same;  vertical  displacement  is  zero),  what  must  be  the  initial  speed  of  the  ball  to  achieve   the  required  distance  (assume  a  perfectly  straight  drive).

bobpursley · Answer

Hmmm. The ball does not roll or bounce?

Time in air:
in the vertical, hf=hi+Vsin15*t-1/2 g t^2
or 0=(VSin15-4.9t)t solve for t.

then horizontal distance..
310yards(39.3inches/yard)(.0254m/inch)=Vcos15*t

solve for V