A boulder is raised above the ground so that the ground is 200j . Then it is dropped. What is its kinetic energy before it hits the ground?
To calculate the kinetic energy of the boulder before it hits the ground, we need to determine its final potential energy and then apply the principle of conservation of energy.
Given:
Potential Energy (PE) = 200 J
When the boulder is dropped, its potential energy is transformed into kinetic energy. In the absence of other forces like air resistance, the total mechanical energy (the sum of potential and kinetic energy) remains constant.
So, to find the kinetic energy, we can equate the potential energy to the kinetic energy just before the boulder hits the ground:
PE = KE
Since Potential Energy (PE) = 200 J, the kinetic energy will also be 200 J just before it hits the ground.
To determine the kinetic energy of the boulder just before it hits the ground, we need to use the principle of conservation of mechanical energy.
According to this principle, the sum of the potential energy and the kinetic energy of an object remains constant throughout its motion, as long as no external forces are acting on it.
In this case, the initial potential energy of the boulder when it is raised above the ground is 200 Joules. As the boulder falls freely without any external forces acting on it (such as air resistance or friction), the potential energy is converted to kinetic energy as it loses height.
Therefore, just before it hits the ground, all the initial potential energy is converted to kinetic energy. Hence, the kinetic energy of the boulder just before it hits the ground is also 200 Joules.