Download Kinetic Energy Lab - Owen County Schools

Name: ___________________________
Date: ________________
Class Period: ________
Unit One- Kinetic Energy
Lab 2- Energy
Introduction:
As we know, kinetic energy is related to mass and speed of an object. Potential energy is related
to the mass and height of an object with an influence from the acceleration due to gravity. When this
unit began, you may have thought that an object at rest has no energy. While I stationary object has no
kinetic energy, it can have potential energy if there are forces acting on it. If it is being pulled on by the
force of gravity, it has gravitational potential energy. For example, a person sitting in a dunk tank has
gravitational potential energy. As soon as the seat under him is pulled away, the force of gravity is no
longer balanced by the opposing force of the seat. Work is done on the person as he falls into the water.
Recall that energy is the ability to do work. Because work is done as the person falls, you know energy
must have been present.
Many forms of energy can be classified into two general types of energy: kinetic energy and
potential energy. The energy of motion is called kinetic energy. The word comes from the Greek work
kinetos, means “moving”. The kinetic energy of any moving object depends upon its mass and speed. To
calculate the kinetic energy of an object in Joules, multiply ½ by the objects mass (m) in kilograms and
the square of its speed (v) in meters per second.
KE= 1/2mv2
Potential energy on the other hand, is energy that is stored as a result of position or shape.
Think of a musician playing a cello. The musician adds energy to the cello string by plucking it. The
energy is stored in the stretched string when the musician pulls it to one side. Then she releases the
string and allows it to vibrate. The stored energy is converted into kinetic energy. You can also store
energy by simply picking up a book and holding it in the air. Let go of the book and that stored energy
will turn into the kinetic energy of motion as the book falls to the floor. Two forms of potential energy as
gravitational potential energy and elastic potential energy.
To find an objects potential energy, we will be using the equation for gravitational potential
energy. This equation uses the acceleration due to gravity. This value is a constant. The acceleration due
to gravity on Earth is 9.8m/s. An objects gravitational potential energy depends on its mass, its height,
and the acceleration due to gravity. The gravitational potential energy an object gains is equal to its
weight (mg) multiplied by its height(h).
PE=mgh
The following series of tasks will help you understand these concepts and give you some insight
and practice on trying to solve them. Each will be done throughout a series of days and then turned in
ALL TOGETHER when the lab days are completed.
Task One
Place a book on the top shelf of a book shelf, on your desk, on a lab bench, etc. use a meter stick
to determine the book’s height and a balance to determine its mass. Then calculate the book’s
gravitational potential energy. When completing the problems, please show ALL WORK! Identify each
value in the equation for potential energy and write it below:
Repeat this process using one other height in the room.
Task two
There are ten types of energy we have talked about in this unit so far. Pick eight forms of energy you can
find in this room and give examples of each. Complete the chart below when showing your examples.
Type of Energy
Example of Energy from Classroom
Task three
Complete the following word problems individually. Calculators are available. SHOW ALL WORK!
1. What is the mass of an object that creates 33,750 joules of energy by traveling at 30
m/sec?
2. What is the kinetic energy of a 2,000-kilogram boat moving at 5 m/sec?
3. What is the potential energy of a 3 kilogram-ball that is on the ground?
4. The potential energy of an apple is 6.00 joules. The apple is 3.00-meters high. What is the mass
of the apple?
5. A car has a mass of 2,000kg and is traveling at 28 meters per second. What is the car’s kinetic
energy?
Task Four
As a group, you will come up with FOUR different objects that are able to roll. These objects will be
brought in on Monday and tested using the ramps. We will determine their kinetic energy and their
potential energy and graph the results. DO NOT forget your objects on Monday! This will be taken for a
grade. To qualify for an object, the object simply must roll. You could even use a pencil or a pen as one
of your objects.
Materials:
4 different rolling objects
Wooden ramp
Timer
Scale
Hypothesis
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Variables
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Constants
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Procedure:
1. Weigh all of the objects before they are placed on the ramp.
Object one: ______________
Object two: _______________
Object Three: _____________
Object four: ______________
2. Measure your ramp using either a ruler or a meter stick
The height of my ramp is: ___________
3. Once you have obtained the height and the weight of each of the objects, using the tape on the
ramp as your starting point, place the object at the top of the ramp.
4. Without pushing the object, roll the object down the ramp. The object should begin rolling as
soon as you let go of it.
5. Begin the timer when your hand leaves the object and stop the timer at the bottom of the ramp.
6. Record each of the times for the object.
7. Repeat steps 3-6 three times FOR EACH OBJECT and put the data in the chart below
Object
Timed trials
Trial one
Trial two
Trial three
Trial one
Trial two
Trial three
Trial one
Trial two
Trial three
Trial one
Trial two
Trial three