In: Physics
If Emily throws the ball at an angle of 30∘ below the horizontal with a speed of 14m/s, how far from the base of the dorm should Allison stand to catch the ball? Assume the vertical distance between where Emily releases the ball and Allison catches it is 8.0m.
Let us consider the downwards direction as positive.
Gravitational acceleration = g = 9.81 m/s2
Initial velocity of the ball = V = 14 m/s
Angle the ball is thrown at = = 30o below the horizontal
Initial horizontal velocity of the ball = Vx = VCos = (14)Cos(30) = 12.12 m/s
Initial vertical velocity of the ball = Vy = VSin = (14)Sin(30) = 7 m/s
Vertical distance between where Emily releases the ball and Allison catches it = H = 8 m
Time taken by the ball to reach Allison = T
T = 0.749 sec or -2.18 sec
Time cannot be negative.
T = 0.749 sec
Horizontal distance traveled by the ball = R
There is no horizontal force acting on the ball therefore the horizontal velocity of the ball remains constant.
R = VxT
R = (12.12)(0.749)
R = 9.08 m
Distance from the base of the dorm Allison should stand to catch the ball = 9.08 m