Work and Energy
Three things are necessary for the
performance of work:
There must be an applied force F.
There must be a displacement x.
The force must have a component
along the displacement.
F
q
F
x
q
If a force does not affect
displacement, it does
Impulse and Momentum
Conservation of Momentum
IMPULSE
F
Dt
Impulse J is a force
F acting for a small
time interval Dt.
Impulse:
J = F Dt
Example 1: The face of a golf club exerts an average force
of 4000 N for 0.002 s. What is the impulse imparted to
the
Torque
&
Equilibrium
Objectives
Define the terms torque, moment arm, and line of
action of a force.
Calculate the resultant torque about any axis given
the magnitude and locations of forces.
Define and apply the vector cross product to
calculate torque
Acceleration
Objectives
Define and apply concepts of average and
instantaneous velocity and acceleration.
Solve problems involving initial and final velocity,
acceleration, displacement, and time.
Solve problems involving a free-falling body in a
gravi
Angular Motion
Objectives
Define and apply concepts of angular
displacement, velocity, and acceleration.
Draw analogies relating rotational-motion
parameters (, , ) to linear (x, v, a) and
solve rotational problems.
Write and apply relationships betwee
Translational Equilibrium
Objectives
Describe with examples Newtons three
laws of motion.
Describe with examples the first
condition for equilibrium.
Draw free-body diagrams for objects in
translational equilibrium.
Apply the first condition for equil
Friction
Friction Forces
When two surfaces are in contact, friction forces
oppose relative motion or impending motion.
P
Friction forces are parallel to
the surfaces in contact and
oppose motion or impending
motion.
Static Friction: No
relative motion.
Ki
Newtons Laws
Newtons Second Law:
Second Law: Whenever a resultant force
acts on an object, it produces an
acceleration: an acceleration that is
directly proportional to the force and
inversely proportional to the mass.
F
a
m
Measuring Mass and Force
The
Practice
Angular Motion
Example 1
A turntable capable of angularly accelerating
at 12 rad/s2 needs to be given an initial
angular velocity if it is to rotate through a net
400 radians in 6 seconds.
What must its initial angular velocity be?
12 rad / s 2