Explanation:
Efficiency is a way of describing the amount of useful output a process or machine can generate as a percentage of the input required to make it go. In other words, it compares how much energy is used to do work versus how much is lost or wasted to the environment. The more efficient the machine, the less energy wasted.
For example, if a heat engine is able to turn 75 percent of the fuel it receives into motion, while 25 percent is lost as heat in the process, it would be 75 percent efficient. Out of the original 100 percent of the fuel, 75 percent was output as useful work.
the equation:
energy efficiency =useful output energy/total input energy
<h2>
Answer:</h2>
The reaction is <u>D. endothermic</u>.
<h2>
Explanation:</h2>
Absorption or need of energy from surroundings is called endothermic process. Heat is the major common form of energy which is absorbed in this process. In this process, enthaply of reactant is less than the product.
For example, an ice cube placed in the hand for some time starts to melt and it takes energy in the form of heat from the hand. This process always requires energy because of the breaking of existing and formation of new chemical bonds.
<h2>The gravitational potential energy is double for stone with twice the mass of other stone.</h2>
Explanation:
Let mass of stone 1 be m.
Mass of stone 2 is twice the mass of stone 1.
Mass of stone 2 = 2m
We know that
Gravitational potential energy = Mass x acceleration due to gravity x Height
PE = mgh
For stone 1 ,
PE₁ = mgh
For stone 2 ,
PE₂ = 2mgh = 2 PE₁
So the gravitational potential energy is double for stone with twice the mass of other stone.
Answer:
Water is absorbing heat.
Explanation:
Water is able to absorb heat
-<u> without increasing much in temperature</u> - better than many substances.
This is because for water to increase in temperature, water molecules must be made to move faster within the water; this requires breaking hydrogen bonds, and the breaking of hydrogen bonds absorbs heat.
<em>the energy that is released in the chemical reactions is the exothermic energy ( stored ) in the bonds of reactants... :)</em>
