Download Dead Week Unit 1 review

Leader: German Parada
Course: Phys 222
Supplemental Instruction
Instructor: Dr. Soeren Prell
Iowa State University
Date: 4/28/2014
Please fill in the blanks and answer the short questions/problems when appropriate.
Dead Week Unit 1 review
Pressure is defined as _____ ____ ____, and it has units of ____. When an object is submerged
in a fluid of density ρ, it experiences pressure dependent on __, ___ and ___, as indicated in the
following equation
where P is the __________ ________ and (P-Po) is
called the _______ __________.
Derived from that equation, Pascal’s principle indicates that:
Due to the difference in hydrostatic pressures, an object submerged in a fluid will experience an
_________ force called ________, which is described in this equation,
When incompressible fluids flow, the volumetric flow rate and velocity are related by the
________ __ ________, which can be written as
. Also, for incompressible
fluids, the conservation of energy allows for the derivation of the Bernoulli equation, which
relates ________, _________, ___________ and fluid ________, as follows
a – Two solid spheres with the same mass but different densities (both lower than that of
water) are tied with rope to the bottom of a pool. If the density of one is three times less than
the other, what is the ratio of the tension of the ropess?
b – Ethanol (ρ = 0.789g/mL) flows in a pipe with decreasing diameter. If the final diameter is
four times narrower than the initial diameter, is the final pressure greater or smaller than the
initial one? How much greater/smaller?
The force between two point charges increases as _______ increases and ______ decreases, as
indicated by the equation
. If more than one charge is present, the force
vectors can be ______ as stated by the __________ ___ ___________.
A more general way of describing forces is by introducing the concept of _______ ________,
obtained by dividing the force over the charge of a test charge. Then, for a point charge, the
expression for the E-field is
. Graphically, the E-filed is represented by
______ _______, which start at _______ charges and end at ________. For multiple charges, the
E-field can also be __________.
To find the E-field for more complex charge, _______ _______ can be used. This law relates the
_________ charge and the E-field, as follows
. Using this law, the
following table can be completed,
Object
E-field
Charged sphere
Surface of charge
Line of charge
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Where the charge densities are,
To calculate the energy and work for electrical systems, a concept called _______ can be used.
The following equation is used to calculate the potential difference between two points
. Usually, the potential at _____ is set at zero. Also, it is possible for find
E-field from potential using
For a point charge, the expression for potential at a point r away is
For constant E-field, the expression for potential is
For conducting objects, the _________ is always zero and the potential is __________.
a- Two identical charges of 30nC are located at (0,0) and (3,0). What is the direction and
magnitude of the E-field at (3,4)?
b – Two parallel lines of charge separated a distance L have charge densities λ1 = -3mC/m
and λ2 = -6mC/m. Where would the net E-field be zero?
c- There are two spheres with the same total charge and radius. However, on is conductive
and while the other is non-conductive and has a uniform charge distribution throughout its
volume. Will the graphs of V(r) for these two spheres be different? How so?
Devices used to store charge are called ______. The measurement of how well the charge is
stored is termed _________ (the unit is ___) and can be found by this equation
.
Different equations can be used to find capacitance for different geometries, as seen below,
Geometry
Parallel Plate
Concentric cylinders
Concentric Spheres
Capacitance
The energy stored by a capacitor can be found with the following equations
In reality, the energy is stored in the _______ ________ inside the capacitor, as shown in the
following equation
If various capacitors are connected in parallel, the equivalent capacitance is found using
whereas the following equation is used if connected in series
If instead of vacuum another material (dielectric) is placed inside the capacitor, the capacitance
expressions need to be multiplied by the ________ _______. This _______ the capacitance of
the devices. However, if the E-field applied across the capacitor is too high, a phenomenon
called ________ ___________ takes place, damaging the capacitor.
a – The plates of a parallel plate capacitor connected to a battery of are pulled away. If the final
separation is three times the initial separation, how does the energy stored change?
b – The dielectric material (k = 3.5) between the plates of an isolated concentric cylinder
capacitor is removed. How does the voltage of this capacitor change? What about the energy?