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 resistance?
A)6.1 m/s
B)7.4 m/s
C)8.1 m/s
D)8.9 m/s

Question

Quizplus · Accepted Answer

The time it takes for the ball to hit the ground is determined by its vertical motion. Using the equation $y = \frac{1}{2}gt^2$, where $y = 24$ m and $g = 9.8$ m/s$^2$, we can solve for $t$. Plugging in the values, we get $t = \sqrt{\frac{2y}{g}} = \sqrt{\frac{2 \times 24}{9.8}} \approx 2.2$ s. The horizontal speed $v$ is constant, and since it covers 18 m in 2.2 s, $v = \frac{18}{2.2} \approx 8.18$ m/s, which rounds to 8.1 m/s.

A Ball Thrown Horizontally from a Point 24 M Above