This preview shows pages 1–4. Sign up to view the full content.
14:440:222 Dynamics
(Lecture Note #9)
Instructor: Prof. Peng Song
Rutgers University
Today’s Lecture
• Work and energy
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document A roller coaster makes use of gravitational forces to assist the
cars in reaching high speeds in the “valleys” of the track.
How can we design the track (e.g., the height, h, and the
radius of curvature
,
ρ
)
to control the forces experienced by
the passengers?
Applications
Crash barrels are often used
along roadways for crash
protection.
The barrels absorb the car’s
kinetic energy by deforming.
If we know the velocity of
an oncoming car and the
amount of energy that can be
absorbed by each barrel,
how can we design a crash
cushion?
Applications (cont’d)
Another equation for working kinetics problems involving
particles can be derived by integrating the equation of
motion (
F
= m
a
) with respect to displacement
.
This principle is useful for solving problems that involve
force, velocity, and displacement
.
It can also be used to
explore the concept of power.
By substituting a
t
= v (dv/ds) into F
t
= ma
t
, the result is
integrated to yield an equation known as the principle of
work and energy
.
To use this principle, we must first understand how to
calculate the work of a force.
Work and Energy
A force does work on a particle when the particle undergoes
a displacement along the line of action of the force.
Work is defined as the product of
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
This document was uploaded on 10/31/2011 for the course ENG MECH 232 at Rutgers.
 Fall '11
 R.C.Hibbeler

Click to edit the document details