A body of mass 5kg falls freely from a height of 100m find
1)initial PE
2)kinetic/potential energy
PE = mgh
I assume you want the KE at the end of the fall.
It will, of course, be equal to the PE at the start.
Otherwise, not sure what (2) means.
To find the initial potential energy (PE) and kinetic energy (KE) of the body, we can use the formulas for gravitational potential energy and kinetic energy.
1) Initial Potential Energy (PE):
The potential energy of an object at a certain height is given by the formula PE = m * g * h, where m is the mass, g is the acceleration due to gravity (approximately 9.8 m/s² on Earth), and h is the height.
In this case, the mass (m) is 5 kg and the height (h) is 100 m. Therefore, the calculation for the initial potential energy is as follows:
PE = m * g * h
= 5 kg * 9.8 m/s² * 100 m
= 4900 J (Joules)
2) Kinetic Energy (KE):
The kinetic energy of an object is given by the formula KE = 0.5 * m * v^2, where m is the mass and v is the velocity of the object.
When the object falls freely, the potential energy converts completely into kinetic energy. At the height of 100 m, the entire potential energy is converted to kinetic energy.
Therefore, we can calculate the kinetic energy using the formula:
KE = PE
Since the potential energy is 4900 J, the kinetic energy will also be 4900 J.
So, the answers are:
1) Initial Potential Energy (PE) = 4900 J
2) Kinetic Energy (KE) = 4900 J