What is the potential energy of a pendulum with a mass of 0.7 kg, a height of 0.3 m, and a value of g equal to 9.8 m/s 2 ?

2.1J

Explanation:

Given parameters:

Mass of pendulum  = 0.7kg

Height of pendulum = 0.3m

Acceleration due to gravity  = 9.8m/s²

Unknown:

Potential energy of the pendulum  = ?

Solution:

The potential energy of a body is the energy due to the position of that body;

 Potential energy  = mass x acceleration due to gravity x height

Insert the parameters and solve;

Potential energy  =0.7kg x 0.3m x 9.8m/s²  

 Potential energy  = 2.1J

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom