# What is the kinetic energy of an object with a mass of 2 kg that has been in freefall for 5 s?

Apr 9, 2018

2401 Joules, approx 2.4kJ

#### Explanation:

Assuming $g = 9.8 m$/${s}^{2}$, initial velocity is zero and NO air resistance.

Use equation $d = {V}_{i} \cdot t + \frac{1}{2} a {t}^{2}$ to find distance:
$d = 4.9 \cdot \left({5}^{2}\right)$
$d = 122.5 m$

Now gravitational potential energy:

${E}_{g} = m g h$
${E}_{g} = 2 k g \cdot 9.8 m \cdot {s}^{-} 2 \cdot 122.5 m$
${E}_{g} = 2401 J$