Applying energy concepts
10-15-12
Section 6.9
With energy, we've got another tool in our physics toolbox to use to attack
problems. Let's try some more examples to see how these energy concepts are
applied.
Air resistance
Air resistance can be a tricky th
Fluid dynamics and Bernoulli's equation
11-10-12
Sections 10.7 - 10.9
Moving fluids
Fluid dynamics is the study of how fluids behave when they're in motion. This
can get very complicated, so we'll focus on one simple case, but we should
briefly mention th
Friction
9-24-12
Sections 4.8 - 4.9
The force of friction
The normal force is one component of the contact force between two objects,
acting perpendicular to their interface. The frictional force is the other
component; it is in a direction parallel to th
Graphical analysis; and Vectors
9-13-12
Sections 2.8 - 3.4
Graphs
Drawing good pictures can be the secret to solving physics problems. It's
amazing how much information you can get from a diagram. We also usually
need equations to find numerical solutions
Gravity
10-6-12
Sections 5.6 - 5.10
The force of gravity
Isaac Newton is probably best known for his study of gravity, seeing as just
about everyone has heard the story about Newton being conked on the head by
an apple. What Newton said was this: whenever
Equilibrium
11-3-12
Sections 9.1 - 9.3
Objects in equilibrium
We've talked about equilibrium before, stating that an object is in equilibrium
when it has no net force acting on it. This definition is incomplete, and it
should be extended to include torque
Constant Acceleration
9-10-12
Sections 2.6 - 2.7
Applying the equations
Doing a sample problem is probably the best way to see how you would use the
kinematics equations. Let's say you're driving in your car, approaching a red
light on Commonwealth Avenue
Assorted forces, and applying Newton's laws
9-22-12
Sections 4.6 - 4.7
Forces can come from various sources. Whenever two objects are touching,
they usually exert forces on each other, Newton's third law reminding us that
the forces are equal and opposite
Center of gravity; and Rotational variables
10-25-12
Sections 7.8 - 8.3
Center of gravity
The center of gravity of an object is the point you can suspend the object from
without there being any rotation because of the force of gravity, no matter how
the o
Collisions
10-22-12
Sections 7.6 - 7.7
A 2-D collision
Because momentum is a vector, whenever we analyze a collision in two or
three dimensions the momentum has to be split up into components. Consider
the following example to see how this works. A 1000 k
Conservation of energy
10-13-12
Sections 6.5 - 6.8
The conservation of mechanical energy
Mechanical energy is the sum of the potential and kinetic energies in a system.
The principle of the conservation of mechanical energy states that the total
mechanica
Introduction to Physics
9-3-12
Sections 1.1 - 1.8 and Appendix A
If you were taking a trip to Greece, you'd get the most out of your trip if you
learned some Greek before going. Knowing a little of the language would help
you somewhat; being fluent in the
Momentum
10-20-12
Sections 7.1 - 7.5
Momentum
There are two kinds of momentum, linear and angular. A spinning object has
angular momentum; an object traveling with a velocity has linear momentum.
For now, and throughout chapter 7, we'll deal with linear m
Torque and rotational inertia
10-27-12
Sections 8.4 - 8.6
Torque
We've looked at the rotational equivalents of displacement, velocity, and
acceleration; now we'll extend the parallel between straight-line motion and
rotational motion by investigating the
Uniform circular motion
9-29-12
Sections 5.1 - 5.2
Uniform circular motion
When an object is experiencing uniform circular motion, it is traveling in a
circular path at a constant speed. If r is the radius of the path, and we define the
period, T, as the
Viscosity and surface tension
11-15-12
Sections 10.10 - 10.13
Real-life fluids
Real-life fluids, like air, water, oil, blood, shampoo, or anything like that, often
don't perfectly obey the fairly straight-forward Bernoulli's principle, and in
some cases B
Work and energy
10-8-12
Sections 6.1 - 6.4
Energy gives us one more tool to use to analyze physical situations. When
forces and accelerations are used, you usually freeze the action at a particular
instant in time, draw a free-body diagram, set up force e
Rotational kinetic energy and angular momentum
11-1-12
Sections 8.7 - 8.9
Rotational work and energy
Let's carry on madly working out equations applying to rotational motion by
substituting the appropriate rotational variables into the straight-line motio
Relative velocity
9-17-12
Section 3.8
Relative velocity in 1 dimension
Most people find relative velocity to be a relatively difficult concept. In one
dimension, however, it's reasonably straight-forward. Let's say you're walking
along a road, heading wes
More circular motion
10-1-12
Sections 5.3 - 5.5
Cars on banked turns
A good example of uniform circular motion is a car going around a banked
turn, such as on a highway off-ramp. These off-ramps often have the
recommended speed posted; even if there was n
Motion in one dimension
9-8-12
Sections 2.1 - 2.5
Motion in 1 dimension
We live in a 3-dimensional world, so why bother analyzing 1-dimensional
situations? Basically, because any translational (straight-line, as opposed to
rotational) motion problem can b
Newton's laws of motion
9-20-12
Sections 4.1 - 4.5
Force
We've introduced the concept of projectile motion, and talked about throwing a
ball off a cliff, analyzing the motion as it traveled through the air. But, how did
the ball get its initial velocity i
Pressure and buoyancy
11-12-12
Sections 10.1 - 10.6
What is a fluid?
You probably think of a fluid as a liquid, but a fluid is simply anything that can
flow. This includes liquids, but gases are fluids too.
Mass density
When we talk about density it's usu
Power
10-18-12
Section 6.10
Power
Being able to do work is not just what's important; how fast you can do work is
also an important factor. Power is the measure of how fast work is done.
Computers have more calculating power than we do; a sports car gener