
Explanation
the density of an object is given by:

Step 1
find the volume of the bar
a)find the volume of the rectangular bar.
the volume of a rectangular prism is given by:

replace

Step 2
now,
Let

replace in the formula

therefore, the answer is

I hope this helps you
48J
Explanation:
Given parameters:
Weight of the book = 16N
Height of the shelf = 3m
Unknown:
Work done to raise the book = ?
Solution:
Work done is defined as the product of force and distance. The force here is the weight of the book which signifies that it was carried in the vicinity of gravitational force.
Work done = Force x distance = weight x distance
Weight is a type of force;
Input the parameters;
Work done = 16 x 3 = 48J
The unit of workdone is in Joules
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Answer:
This does not violate the conservation of energy.
Explanation:
This does not violate the conservation of energy because the hot body gives energy in the form of heat to the colder body, this second absorbs energy. This will be the case until both bodies reach the same temperature, reaching thermal equilibrium and reducing the transfer of thermal energy. In this way the energy was only transferred from one body to another but the total energy of the system (body 1 plus body 2) will be the same as in the beginning, respecting the principle of conservation of energy or also called the first principle of thermodynamics .
The part of physics that studies these processes is in turn called heat transfer or heat transfer or thermal transfer. Heat transfer occurs whenever there is a thermal gradient or when two systems with different temperatures come into contact. The process persists until thermal equilibrium is reached, that is, until temperatures are equalized. When there is a temperature difference between two objects or regions close enough, the heat transfer cannot be stopped, it can only be slowed down.
When storm clouds produce lightening and thunder, then, potential energy changes into kinectic energy.
The clouds become negatively charged,and the ground is positively charged during a storm. So there creates a potential difference between the charged clouds and the ground. And when this becomes huge so much that it over comes the electrical insulation cover of air, the electrons jump to the ground.i.e. the potential energy changes into kinetic energy.