Question

Determine the mechanical energy of this object: a 1-kg ball sits on a 10-meter high cliff.

A. The ball isn't moving, so the mechanical energy is zero
B. 10 J
C. 98 J
D. 980 J

Also could you explain how you did it because i have know idea how to solve it

Answer 1

The answer would be 98 J

Answer 2

C. 98 J

Step-by-step explanation:

Mechanical energy is defined as the sum of kinetic energy (K) and potential energy (U):

E = K + U

where

`K=(1)/(2)mv^2` is the kinetic energy, where m is the mass of the object and v its speed

`U=mgh` is the potential energy, where g is the gravitational acceleration and h the height of the object relative to a reference point

For the object in this problem, the kinetic energy is zero, because it is not moving, so v = 0 and K=0. So the mechanical energy is just given by the potential energy, which is given by:

`E=U=mgh=(1 kg)(9.8 m/s^2)(10 m)=98 J`