Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Work Defined
Name: Brittany
Status: student
Age: 13
Location: N/A
Country: N/A
Date: 1999 

If you lift a 10lb weight it is considerd doing work, but if you walk a mile with that same weight is it considerd the same type of work? If so, what is the difference between the two?

Brittany -

Work is force times distance. It makes no difference in what direction. However, if you lift the object farther above the ground, you have added potential energy (energy of position). If you move the object horizontally, you have still done work, but have added no potential energy.

In the case of lifting the object, because you have stored energy (defined as the ability to do work) you could use it to do work. Just let it go and it will fall. Force times distance...

The energy of position is sometimes called GPE - gravitational potential energy. This differentiates it from potential energy such as chemical potential energy.

work = force times distance

joules = newtons times meters (at least in the metric system)

Do you know what a "slug" is? It is a unit of measure you might want to look up.

Larry Krengel

It's not the same. In the first case, you're moving something against a constant opposing force. The work done is the force you're exerting multiplied by the distance the weight moves while you're exerting the force.

In the second case the only work done is in getting the weight from a standstill to walking speed (I'll assume you're walking in a straight line at constant speed -- i.e., no accelerations). Ideally, once you have the weight moving you just let it coast. It feels like work to you, because muscles use energy just to maintain tension, but the work is not being done on the weight.

Tim Mooney

Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory