Find the height of the frog at the instant the stick hits the ground:

1.56 m

Explanation:

The center of mass is initially at a height of 1.80 m.  After 0.42 seconds, it falls to a height of:

y = y₀ + v₀ t + ½ at²

y = 1.80 + (0)(0.42) + ½ (-9.8)(0.42)²

y = 0.936

Using definition of center of gravity:

(7.05 + 4.70) (0.936) = (7.05) h + (4.70) (0)

h = 1.56

The frog's height is 1.56 meters (remember to round to the same number of significant figures as the data provided).

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