PHYS1420
Fall 2013
Ch. 4.5 Applications of Newtons Laws
1
Applications of Newtons Laws
Assumptions
Objects behave as particles
Can ignore rotational motion (for now)
Masses of strings or ropes are negligible
Interested only in the forces acting on th
PHYS1420
Fall 2014
Ch. 7.1 Angular Speed and Angular
Acceleration
1
Angular Motion
Will be described in terms of
Angular displacement,
Angular velocity,
Angular acceleration,
Analogous to the main concepts in linear
motion
2
The Radian
The radian
PHYS1420
Fall 2014
Ch. 6.1 Momentum and Impulse
1
Collisions
Conservation of momentum allows complex collision
problems to be solved without knowing about the
forces involved
Information about the average force can be derived
2
Momentum
The linear mome
PHYS1420
Fall 2014
Ch. 5.1 Work
1
Forms of Energy
Mechanical
Focus for now
May be kinetic (associated with motion) or
potential (associated with position)
Chemical
Electromagnetic
Nuclear
Contained in mass
2
Some Energy Considerations
Energy can be tr
PHYS1420
Fall 2014
Ch. 3.1 Vectors and Their Properties
1
Vector vs. Scalar
All physical quantities encountered in this text will be
either a scalar or a vector
A vector quantity has both magnitude (size) and
direction
Velocity, acceleration, force
A
PHYS1420
Fall 2014
Ch. 2.1 Displacement
1
Coordinate system
Change in position with time motion.
To measure position specify the coordinate
system and its origin.
Example:
xi
xf
X
0
1
2
3
4
5
Initial position xi, final position xf. If the
origin is de
PHYS1420
Fall 2014
Ch. 4.1 Forces
1
Classical Mechanics
Describes the relationship between the
motion of objects in our everyday world and
the forces acting on them
Conditions when Classical Mechanics does not
apply
Very tiny objects (< atomic sizes)
PHYS1420
Fall 2014
Ch. 8.6 Rotational Kinetic Energy
1
Rotational Kinetic Energy
An object rotating about some axis with an
angular speed, , has rotational kinetic energy
KEr = I2
Here, I is the moment of inertia of the object.
Energy concepts can be u
PHYS1420
Fall 2014
Ch. 9.2 Density and Pressure
1
Density
The density of a substance of uniform
composition is defined as its mass per unit
volume:
m
V
SI unit: kg/m3 (SI)
Often see g/cm3 (cgs)
1 g/cm3 = 1000 kg/m3
2
Density, cont.
See table 9.1 for
PHYS1420
Fall 2014
Ch. 8.1 Torque
1
Force vs. Torque
Forces cause accelerations
Torques cause angular accelerations
Force and torque are related
The point of application of a force is important
This was ignored in treating objects as point
particles
2
To
PHYS1420
Fall 2013
Ch. 7.1 Angular Speed and Angular
Acceleration
1
Angular Motion
Will be described in terms of
Angular displacement,
Angular velocity,
Angular acceleration,
Analogous to the main concepts in linear
motion
2
The Radian
The radian
PHYS1420
Fall 2013
Ch. 7.3 Relations Between Angular
and Linear Quantities
1
Rotation of an object
Point P moves through
the angle in the
interval t. The radian
measure is defined as:
s
r
At the same time, the
angular velocity is:
av
t
2
Angular vs.
PHYS1420
Fall 2013
Ch. 5.6 Power
1
Power
Design of practical devices: electrical appliances and
engines
Often also interested in the rate at which the energy
transfer takes place
Power is defined as this rate of energy transfer (work
done on an object
PHYS1420
Fall 2013
Ch. 6.1 Momentum and Impulse
1
Collisions
Conservation of momentum allows complex collision
problems to be solved without knowing about the
forces involved
Information about the average force can be derived
2
Momentum
The linear mome
PHYS1420
Fall 2013
Ch. 6.4 Glancing Collisions
1
Glancing Collisions
For a general collision of two objects in threedimensional space, the conservation of momentum
principle implies that the total momentum of the
system in each direction is conserved
m1v
PHYS1420
Fall 2013
Ch. 8.6 Rotational Kinetic Energy
1
Rotational Kinetic Energy
An object rotating about some axis with an
angular speed, , has rotational kinetic energy
KEr = I2
Here, I is the moment of inertia of the object.
Energy concepts can be u
PHYS1420
Fall 2013
Ch. 2.1 Displacement
1
Coordinate system
Change in position with time motion.
To measure position specify the coordinate
system and its origin.
Example:
xi
xf
X
0
1
2
3
4
5
Initial position xi, final position xf. If the
origin is de
PHYS1420
Fall 2013
Ch. 8.3 The Center of Gravity
1
Center of Gravity
The force of gravity acting on an object must be
considered
General rule: In finding the torque produced by
the force of gravity, all of the weight of the object
can be considered to b
PHYS1420
Fall 2013
Ch. 7.2 Rotational Motion Under
Constant Acceleration
1
Angular Speed
Example: average angular speed and average
linear speed:
f i
av
t f ti
t
x f xi
x
vav
t f ti
t
2
Analogies Between Linear and
Rotational Motion
There are many pa
PHYS1420
Fall 2013
Ch. 8.2 Torque and the Two
Conditions for Equilibrium
1
Torque and Equilibrium
First Condition of Equilibrium
The net external force must be zero
F 0 or
Fx 0 and
Fy 0
This is a statement of translational equilibrium
The Second Co
PHYS1420
Fall 2013
Ch. 2.5 One-Dimensional Motion
with Constant Acceleration
1
Acceleration
Average
acceleration of
the car:
a
v f vi
t f ti
2
Constant acceleration
v velocity at any time t
The average acceleration
is equal to the instantaneous
acceler
PHYS1420
Fall 2013
Ch. 3.2 Components of a Vector
1
Vector projections
It is useful to use
rectangular
components to add
vectors
These are the
projections of the
vector along the x- and
y-axes: Ax and Ay
Angle is measured
counterclockwise from
the posi
PHYS1420
Fall 2013
Ch. 3.3 Displacement, Velocity, and
Acceleration in Two Dimensions
1
Displacement
The position of an object is
described by its position
vector, r
The displacement of the
object is defined as the
change in its position
r rf ri
SI