Question

If you drop a steel metal ball off a building and it takes 3 seconds to hit

Answer 1

Answer:

$40\:\mathrm{m}$

Explanation:

We can use kinematics equation $\Delta y={v_i}^2+\frac{1}{2}at^2$ to solve this problem. Because the metal ball's initial velocity was 0, ${v_i}^2=0$.

Therefore, our equation becomes:

$\Delta y=\frac{1}{2}at^2$ (freefall equation).

$t$ is given as 3 seconds and $a$ is acceleration due to gravity ($9.81\:\mathrm{m/s}$).

Therefore, our answer is:

$\Delta y = \frac{1}{2}\cdot9.81\cdot3^2=44.145=\fbox{ 40\:\mathrm{m} }$ (one significant figure).