Mechanical energy is the energy possessed by an object due to its motion or its position. It is the sum of kinetic energy and potential energy in an object. Kinetic energy is the energy of motion, while potential energy is the energy associated with an object's position or state.

Kinetic Energy

Kinetic energy is the energy an object possesses due to its motion. The formula for kinetic energy is:

KE = 1/2 * m * v^2

Where:
KE = kinetic energy
m = mass of the object
v = velocity of the object

Potential Energy

Potential energy is the energy stored in an object due to its position or state. The formula for potential energy depends on the specific type of potential energy, such as gravitational potential energy or elastic potential energy.

Gravitational Potential Energy

The gravitational potential energy of an object near the surface of the Earth can be calculated using the formula:

PE = m * g * h

Where:
PE = potential energy
m = mass of the object
g = acceleration due to gravity
h = height of the object above a reference point

Elastic Potential Energy

The elastic potential energy of an object, such as a spring, can be calculated using the formula:

PE = 1/2 * k * x^2

Where:
PE = potential energy
k = spring constant
x = displacement from the equilibrium position

Conservation of Mechanical Energy

According to the law of conservation of energy, the total mechanical energy of an object remains constant if only conservative forces (such as gravity or spring forces) are acting on it. This means that the sum of the kinetic and potential energies in a system remains constant, unless non-conservative forces (such as friction) are present.

Study Guide

Define mechanical energy and its components.
Discuss the formula for kinetic energy and provide examples of its application.
Explain gravitational potential energy and how it is calculated.
Describe elastic potential energy and provide examples of objects exhibiting this type of potential energy.
Discuss the concept of conservation of mechanical energy and its implications.

◂Science Worksheets and Study Guides Eighth Grade. Chemical reactions

Vocabulary/Answer key

Chemical reactions

Vocabulary/Answer key

Chemical reactions

The resources above cover the following skills:

Chemistry: Students will use scientific skills and processes to explain the composition, structure, and interactions of matter in order to support the predictability of structure and energy transformations.

Conservation of Matter: Provide evidence to support the fact that the idea of atoms explains conservation of matter.

Cite evidence from investigations that the total mass of a system remains the same throughout a chemical reaction because the number of atoms of each element remains the same.

Give reasons to justify the statement, 'If the number of atoms stays the same no matter how the same atoms are rearranged, then their total mass stays the same.'

Physical and Chemical Changes: Provide evidence to support the fact that common substances have the ability to change into new substances.

Investigate and describe the occurrence of chemical reactions using the following evidence: Color change; Formation of a precipitate or gas; Release of heat or light.

Use evidence from observations to identify and describe factors that influence reaction rates: Change in temperature; Acidity.

Identify the reactants and products involved in a chemical reaction given a symbolic equation, a word equation, or a description of the reaction.

Provide data from investigations to support the fact that energy is transformed during chemical reactions.