Question

What is the potential energy of a 3.00 kg object at the bottom of a well 10.0 m deep as measured from ground level ? Explain the sign of the answer. (b) How much qirk is required to lift a 3.00 kg object from the bottom of the well 10.0 m deep

Answer 1

The potencial energy is given by the following formula:

$E_P=\text{mgh}$

Where "m" is the mass, "g" is the acceleration of gravity, and "h" is the height. Since the height is below the reference point it has a negative sign. Replacing we get:

$E_P=(3kg)(9.8\frac{m}{s^2})(-10m)$

Solving the operation:

$E_P=-294J$

The negative sign indicates that the object is below the zero point.

b. Since the work is equivalent to:

$W=Fd$

The force that acts on the object is equivalent to its weight and the distance the height, therefore:

$W=\text{mgh}$

Replacing:

$\begin{gathered} W=(3\operatorname{kg})(9.8\frac{m}{s^2})(10m) \\ W=294J \end{gathered}$