Answer;
D - 1,960 J, 3,720 J
Step-by-step explanation;
- The stone is initially at a height of 100 m from where it is dropped. The gravitational potential energy of an object with mass m at a height h from the ground is PE = mgh where g is the acceleration due to gravity.
- At a height of 145 m from the ground, the potential energy of the 3 kg stone is 4×9.8×145 = 5,684 J, approximately; 5680 Joules.
At a height of 50 m from the ground, the potential energy will be;
= 4 × 9.8 × 50
= 1960 Joules
This means that some of the energy possessed by the stone at a height of 145 m was converted to kinetic energy.
Therefore; the energy that was converted to kinetic energy will be;
= 5,680 J - 1960 J
= 3,724 Joules
Approximately kinetic energy is 3,720 Joules
Therefore;
The Potential energy is 1960 Joules and Kinetic energy is 3,720 Joules