What is the kinetic energy of an object with a mass of #9 kg# that has been in freefall for #1 s#?
The kinetic energy, in classical mechanics, it is
You have the mass, so you need to calculate the velocity.
Your body is in free fall, this means that it is subject to the gravity that accelerates with a constant strength.
The acceleration is the change of velocity during the time. So we can write:
With the velocity we can calculate the energy
We can think of our system in which the object was placed at a certain height and then released. Now, when it was placed at the initial position it gained a certain Potential Energy
We know that:
From kinematics we have:
considering the ground as