Answer to Question #102201 in Mechanics | Relativity for grr

Question

Suppose Ichiro threw a rock upward with an initial velocity of 8.0 m/s. Determine the velocity and displacement of the rock at 4 s.

Answer 1

$v_0=8.0\; m/s$

$a=-9.8\; m/s^2$

$t=4\;s$

$v, \Delta y \;-\;?$

Solution:

$v=v_0+at$

$v=8.0+(-9.8)\times4=-31.2 \; m/s$

$\Delta y=v_0t+\frac{1}2at^2$

$\Delta y=8.0\times 4+\frac{1}{2}(-9.8)\times 4^2=-46.4 \;m$

Answers: $v=-31.2\; m/s, \; \Delta y=-46.4\; m.$