Question

You drop your frozen rock from a green bridge. The frozen rock starts from rest (initial velocity = 0ms). The rock takes 4.3s to hit the water below. The acceleration due to gravity on Earth is 9.8m\s2 s 2 downward. What is the frozen rocks velocity after 1.5 seconds? vf = vi + at

Answer 1

Answer:

The velocity of the frozen rock at $t = 1.5\,s$ is -14.711 meters per second.

Explanation:

The frozen rock experiments a free fall, which is a type of uniform accelerated motion due to gravity and air viscosity and earth's rotation effect are neglected. In this case, we need to find the final velocity ($v$), measured in meters per second, of the frozen rock at given instant and whose kinematic formula is:

$v = v_{o} + g\cdot t$ (Eq. 1)

Where:

$v_{o}$ - Initial velocity, measured in meters per second.

$g$ - Gravity acceleration, measured in meters per square second.

$t$ - Time, measured in seconds.

If we get that $v_{o} = 0\,\frac{m}{s}$, $g = -9.807\,\frac{m}{s^{2}}$ and $1.5\,s$, then final velocity is:

$v = 0\,\frac{m}{s}+\left(-9.807\,\frac{m}{s^{2}} \right) \cdot (1.5\,s)$

$v = -14.711\,\frac{m}{s}$

The velocity of the frozen rock at $t = 1.5\,s$ is -14.711 meters per second.