a marble is shot horizontally from a table .8 m High, and it lands, 1.2 meters away horizontally. what was the initial velocity of the marble as it left the table

3 m/s

Explanation:

First, find the time it takes to land.

Given in the y direction:

Δy = 0.8 m

v₀ = 0 m/s

a = 10 m/s²

Find: t

Δy = v₀ t + ½ at²

0.8 m = (0 m/s) t + ½ (10 m/s²) t²

t = 0.4 s

Next, find the velocity needed to travel 1.2 m in that time.

Given in the x direction:

Δx = 1.2 m

a = 0 m/s²

t = 0.4 s

Find: v₀

Δx = v₀ t + ½ at²

1.2 m = v₀ (0.4 s) + ½ (0 m/s²) (0.4 s)²

v₀ = 3 m/s

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