what is the between atoms and molecules? how do compounds and elements differ?

A new type of 38.0 W lamp is designed to produce the same illumination as a conventional 53.0 W lamp. How much energy does this lamp save during 370.0 h of use? Answer in units of J.

If electrical energy costs $0.080/kW·h, how much money is saved in 370.0 h? Answer in units of $.

In Fig. 8.3, a bullet of mass 0.01 kg moving horizontally strikes a block of wood of mass 1.5 kg which is suspended as a pendulum. The bullet lodges in the wood, and together they swing upward a distance of 0.40 m. What was the velocity of the bullet just before it struck the wooden block? The length of the string is 2 meters.

A 100 cm^3 box contains helium at a pressure of 1.60 atm and a temperature of 120 ∘C. It is placed in thermal contact with a 190 cm^3 box containing argon at a pressure of 4.20 atm and a temperature of 390 ∘C.

What is the initial thermal energy of each gas?

What is the final thermal energy of each gas?

How much heat energy is transferred?

What is the final temperature?

What is the final pressure in each box?

The point charges in the figure below have the following values: q₁ = +2.7

Two hard rubber spheres, each of mass m = 13.8 g, are rubbed with fur on a dry day and are then suspended with two insulating strings of length L = 5.25 cm whose support points are a distance d = 2.70 cm from each other as shown in the figure below. During the rubbing process, one sphere receives exactly twice the charge of the other. They are observed to hang at equilibrium, each at an angle of θ = 10.7° with the vertical. Find the amount of charge on each sphere. (Assume the two spheres have charges q₁ and q₂ = 2q₁)

Deep-sea divers often breathe a mixture of helium and oxygen to avoid the complications of breathing high-pressure nitrogen. At great depths the mix is almost entirely helium, which has the side effect of making the divers' voices sound very odd. Breathing helium doesn't affect the frequency at which the vocal cords vibrate, but it does affect the frequencies of the formants. The text gives the frequencies of the first two formants for an "ee" vowel sound as 270 and 2300 Hz.

What will these frequencies be for a helium-oxygen mixture in which the speed of sound at body temperature is 720m/s ? (Use 350 m/s for the speed of sound in the air.)

A positive charge q is fixed at the point x = 0, y = 0, and a negative charge -2q is fixed at the point x = a, y = 0.

a) Derive an expression for the potential V at points on the x -axis as a function of the coordinate x . Take V to be zero at an infinite distance from the charges. (Express your answer in terms of the given quantities and appropriate constants).

V(x) =

b) At which positions on the x -axis is V = 0? (Enter your answers numerically separated by commas).

x/a =

c) What does the answer to part A become when x>>a ?

V =

d) Explain why this result is obtained.

An astronaut has left the International Space Station to test a new space scooter. Her partner measures the following velocity changes, each taking place in a time interval 10.9 s . What are the average acceleration in each interval? Assume that the positive direction is to the right.

Part A

At the beginning of the interval the astronaut is moving toward the right along the x-axis at 14.1 m/s , and at the end of the interval she is moving toward the right at 5.50 m/s .

Part B

At the beginning she is moving toward the left at 5.50 m/s , and at the end she is moving toward the left at 14.1 m/s .

Part C

At the beginning she is moving toward the right at 14.1 m/s , and at the end she is moving toward the left at 14.1 m/s .

1. how does proton therapy work

2. Clinical application of proton therapy

a)Find the x-component of vector v⃗  = (310 m/s , 45 ∘ above +x-axis).

b)Find the y-component of vector v⃗  = (310 m/s , 45 ∘ above +x-axis).

The average intensity of a particular TV station

Which of the following statements are true?
True False  Magnetic field lines always start at a North and end at a South pole.
True False  When placing a dipole magnet into a magnetic field, it will be accelerated perpendicular to the field lines.
True False  The force on a moving charge is perpendicular to both the field and its velocity.
True False  The larger the charge of a moving particle, the more it will accelerate inside of a magnetic field.

Which  process, conduction, convection, or radiation is most involved with the  distribution of heat around the earth?

Write about czochralski method (melt) in half of a sheet