Problem #9: A pebble falls from a bridge into the river below. If the pebble falls for 1.20 s, what is its

velocity when it hits the water?

-11.0 m/s

-8.17 m/s

-11.8 m/s

11.8 m/s

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 0 m/s

Time (t) = 1.2 s

Acceleration due to gravity (g) = 9.8 m/s²

Final velocity (v) =...?

The velocity, v, with which the pebble hits the water can be obtained as follow:

v = u + gt

v = 0 + 9.8 × 1.2

v = 0 + 11.76

v = 11.76 ≈ 11.8 m/s

Thus, the pebble hits the water with a velocity of 11.8 m/s

the answer is 100. i just did this lesson and got a 100% on it. : )

-fishtank