# What is the kinetic energy of an object with a mass of 7 kg that has been in freefall for 3 s?

Kinetic Energy $K E = 3025.26 \text{ }$joules

#### Explanation:

The given data are as follows
mass $m = 7 \text{ }$kg
time $t = 3 \text{ }$seconds

Assuming it starts from rest at ${v}_{0} = 0$

${v}_{f} = {v}_{0} + g \cdot t$

${v}_{f} = 0 + \left(- 9.8\right) \left(3\right)$

${v}_{f} = - 29.4 \text{ }$m/sec

Kinetic Energy

$K E = \frac{1}{2} m {v}^{2}$

$K E = \frac{1}{2} \cdot 7 \cdot {\left(- 29.4\right)}^{2}$

$K E = 3025.26 \text{ }$joules

God bless...I hope the explanation is useful.