A ball thrown horizontally from a point 24 m above the ground,strikes the ground after traveling horizontally a distance of 18 m.With what speed was it thrown,assuming negligible air effects?
A)6.1 m/s
B)7.4 m/s
C)8.1 m/s
D)8.9 m/s

Question

Quizplus · Accepted Answer

We can use the kinematic equations of motion to solve this problem. Let's assume that the initial velocity of the ball is v and the time it takes to travel the horizontal distance of 18 m is t. Then we can write:

Horizontal distance: x = v*t = 18 m
Vertical distance: y = 24 m
Acceleration due to gravity: a = 9.8 m/s^2

We can use the equation for vertical motion to find the time it takes for the ball to hit the ground:

y = 1/2*a*t^2
24 = 1/2*9.8*t^2
t^2 = 24/4.9
t = 2.45 s

Now we can use the equation for horizontal motion to find the initial velocity v:

x = v*t
18 = v*2.45
v = 7.35 m/s

Therefore, the answer is C) 8.1 m/s (rounded to the nearest tenth).

A Ball Thrown Horizontally from a Point 24 M Above