Exercício de Dinamica Aplicada (53)

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214 
 
 
PROBLEM 11.145 
A golfer hits a golf ball from Point A with an initial velocity of 50 m/s 
at an angle of 25° with the horizontal. Determine the radius of curvature 
of the trajectory described by the ball (a) at Point A, (b) at the highest 
point of the trajectory. 
 
SOLUTION 
(a) We have 
2
( ) A
A n
A
v
a
ρ
= 
 or 
2
2
(50 m/s)
(9.81 m/s )cos 25
Aρ =
°
 
 or 281 mAρ =  
(b) We have 
2
( ) B
B n
B
v
a
ρ
= 
 where Point B is the highest point of the trajectory, so that 
 ( ) cos 25B A x Av v v= = ° 
 Then 
2
2
[(50 m/s) cos 25°] 
9.81 m/s
Bρ = 
 or 209 mBρ = 