Kinetic energy

Physical Chemistry

In the photoelectric effect an electron is emitted from a metal as the result of absorption of a photon of light. Part of the energy of the photon is required to release the electron from the metal; this energy $\phi$ is called the work function or binding energy. The kinetic energy of the ejected electron is given by
\[
\frac{1}{2} m v^{2}=h \nu-\phi
\]
where $m$ and $v$ are the mass and velocity of the electron. For the 100 face of silver metal (see Chapter 23 ) the velocity of electrons emitted using 200 -nm photons is $7.42 \times 10^{5} \mathrm{m} \mathrm{s}^{-1}$. Calculate the work function of this face in eV.

Quantum Theory

02:10

Engineering Mechanics: Statics and Dynamics

The assembly weighs 10 lb and has a radius of gyration $k_{G}=0.6 \mathrm{ft}$ about its center of mass $G .$ The kinetic energy of the assembly is $31 \mathrm{ft} \cdot 1 \mathrm{b}$ when it is in the position shown. If it rolls counterclockwise on the surface without slipping, determine its linear momentum at this instant.

Planar Kinetics of a Rigid Body: Impulse and Momentum

03:13

Engineering Mechanics: Statics and Dynamics

The double pulley consists of two parts that are attached to one another. It has a weight of $50 \mathrm{lb}$ and a centroidal radius of gyration of $k_{O}=0.6 \mathrm{ft}$ and is turning with an angular velocity of 20 rad/s clockwise. Determine the kinetic energy of the system. Assume that neither cable slips on the pulley.

Planar Kinetics of a Rigid Body: Work and Energy

Work Energy Theorem

132 Practice Problems

01:37

Thermodynamics : An Engineering Approach

Consider two geothermal wells whose energy contents are estimated to be the same. Will the exergies of these wells necessarily be the same? Explain.

Energy

05:14

Thermodynamics : An Engineering Approach

A gas is compressed from an initial volume of $0.42 \mathrm{m}^{3}$ to a final volume of $0.12 \mathrm{m}^{3} .$ During the quasi-equilibrium process, the pressure changes with volume according to the relation $P=a V+b,$ where $a=-1200 \mathrm{kPa} / \mathrm{m}^{3}$ and $b=600 \mathrm{kPa}$
Calculate the work done during this process ( $a$ ) by plotting the process on a $P$ - $V$ diagram and finding the area under the process curve and ( $b$ ) by performing the necessary integrations.

Energy Analysis of Closed Systems

04:06

Thermodynamics : An Engineering Approach

1-m^{3}$ of saturated liquid water at $200^{\circ} \mathrm{C}$ is expanded isothermally in a closed system until its quality is 80 percent. Determine the total work produced by this expansion, in kJ.

Energy Analysis of Closed Systems

Work Done by a Constant Force

124 Practice Problems

01:15

Thermodynamics : An Engineering Approach

Can a process for which the reversible work is zero be reversible? Can it be irreversible? Explain.

Energy

00:58

Thermodynamics : An Engineering Approach

Consider a process that involves no irreversibilities. Will the actual useful work for that process be equal to the reversible work?

Energy

02:06

Thermodynamics : An Engineering Approach

How does useful work differ from actual work? For what kind of systems are these two identical?

Energy

Work Done by a Varying Force

81 Practice Problems

03:20

Thermodynamics : An Engineering Approach

A mass of 5 kg of saturated water vapor at 300 kPa is heated at constant pressure until the temperature reaches $200^{\circ} \mathrm{C} .$ Calculate the work done by the steam during this process.

Energy Analysis of Closed Systems

03:20

Thermodynamics : An Engineering Approach

A piston-cylinder device initially contains $0.07 \mathrm{m}^{3}$ of nitrogen gas at $130 \mathrm{kPa}$ and $180^{\circ} \mathrm{C}$. The nitrogen is now expanded to a pressure of $80 \mathrm{kPa}$ polytropically with a polytropic exponent whose value is equal to the specific heat ratio (called isentropic expansion). Determine the final temperature and the boundary work done during this process.

Energy Analysis of Closed Systems

05:19

Thermodynamics : An Engineering Approach

A piston-cylinder device with a set of stops initially contains $0.6 \mathrm{kg}$ of steam at $1.0 \mathrm{MPa}$ and $400^{\circ} \mathrm{C}$. The location of the stops corresponds to 40 percent of the initial volume. Now the steam is cooled. Determine the compression work if the final state is $(a) 1.0 \mathrm{MPa}$ and $250^{\circ} \mathrm{C}$ and (b) 500 kPa. (c) Also determine the temperature at the final state in part $(b)$.

Energy Analysis of Closed Systems