To find the velocity of the ball just before it strikes the ground, we can use the equations of motion. Since the ball is thrown horizontally, the initial vertical velocity is zero.
Let's denote the time taken for the ball to hit the ground as 't', the initial horizontal velocity as 'v', and the acceleration due to gravity as 'g' (approximately 9.8 m/s²).
Using the equation of motion for vertical displacement, we can determine the time it takes for the ball to reach the ground: h = (1/2)gt²
Substituting the known values, we have: 80 = (1/2)(9.8)t²
Simplifying the equation: t² = (80 * 2) / 9.8 t² = 16.3265 t ≈ 4.04 seconds
Now, we can use the equation of motion for horizontal displacement to find the initial horizontal velocity: d = vt
Substituting the known values: 64 = v * 4.04
Solving for 'v': v = 64 / 4.04 v ≈ 15.84 m/s
Therefore, the velocity of the ball just before it strikes the ground is approximately 15.84 m/s horizontally.