When we receive an X-ray at the dentist office why do they place a lead apron on our chest? Why is it lead? What type of radiation?

Why do dictators hold elections? (comparative politics)

A sample of butane gas, C4H10, was slowly heated at constant pressure of .80 bar. The volume of the gas was measured a series of different temperatures and plot of volume vs. temperature was constructed. The slope of the line was .0208 L/K. What was the mass of the sample of butane? Please explain.

A 55.0 mL solution of 0.126 M potassium alaninate (H2NC2H5CO2K) is titrated with 0.126 M HCl. The pKa values for the amino acid alanine are 2.344 (pKa1) and 9.868 (pKa2), which correspond to the carboxylic acid and amino groups, respectively. a) how do you calculate the PH of the first equivalent and b) the second equivalent? please help

A parallel plate capacitor with plate area 100.0cm² and air-gap separation .500mm is connected to a 12.0 V battery, and fully charged. The batter is then disconnected.

A.) The plates are now pulled to a separation of 1.00mm. What is the magnitude of the charge on each capacitor plate and the magnitude of the E-field between the plates now? ( ?₀ = 8.85 x 10^-12 C²/Nm²)

B.) What is the potential difference across the plates now?

C.) How much work was required to pull the plates to their new separation?

D.) If a proton was released from the + plate and hit the - plate, what speed would it have?

Thanks :D

Consider a company which owns a license of Class C network (207.84.123.0), This Company wants to create 14 subnetworks.
1.
Determine the number of bits borrowed
2.
How many bits are then used for the subnet ID?
Determine the maximum number of hosts in each subnet
3.
Determine the subnet mask of this scheme
4.
Determine the first, the forth and the last network (subnet) addresses
5.
Determine the first host address, the last host address and the broadcast address in only the first subnet.
6.
7. To which subnet belongs the host having the address 207.84.123.181?

Suggest with proper explanation 10 reasons about which web framework is likely to at the forefront of technology in the next decades.

NOTE: NO plagiarism from the internet it should be typed in your OWN WORDS PLEASE.

a) Describe the glass transition temperature of polymers and ceramics

b) Compare and contrast the rules that underly the formation of crystalline structures in ceramics and polymers

A 20 g ball of clay traveling east at 3.0 m/s collides with a 30 g ball of clay traveling north at 2.0 m/s. What is the magnitude and direction of initial momentum for each ball before collision? a. What is the momentum of 50 g blob of clay in x? What is the speed in that same direction? b. What is the momentum of 50 g blob of clay in y? What is the speed in that same direction? c. What is the resultant speed of the blob? d. What is direction of the blob?

A placekicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 23.4 m/s at an angle of 48.0° to the horizontal.

(a) By how much does the ball clear or fall short of clearing the crossbar? (Enter a negative answer if it falls short.)
m
(b) Does the ball approach the crossbar while still rising or while falling?

rising or falling

You and your spouse have decided that now is a good time to "buy vs. own." You have found a dream house that costs 278970 and you can get an loan-to-value of 89%. Your broker has lined up a traditional, fully amortizing loan at an interest rate of 6 annual, compounded 12/year for a 30 year term. What will your mortgage payments be if you buy the house?

You have taken on a new job that will be extremely intense and not leave much time for vacations. Your significant other is willing to put up with things but wants you to promise to take them on a dream vacation at the end of the 5th year. Since you haven't been able to deliver on these promises in the past, they want you to set aside enough money to cover that cruise which will cost $13835. If you can earn 5% annual, compounded monthly, how much will you have to set aside?

You are putting together a partnership and want to bring in a partner who is very focused on building up his wealth. You have run your cash flows and think you can promise to give him a constant annual dividend of 23109. Assume he can earn 6% compounded 1 times per year on his money. He wants to know what the investment will accumulate to if you run the partnership for 8 years. What will he have accumulated in his account by then?

You are worried about the future of social security and want to start saving. You think you can set aside $1606 per month. You have been offered an investment product on which you can earn 3% annually compounded 12 times per year. How much will this accumulate to if you plan to retire at the end of the 10th year?

The energy of light photons varies with wavelength. Calculate the energy per mole of photons for each of the following colors of visible light. Red Light, ? = 691 nm Green Light, ? = 527 nm Blue Light, ? = 411 nm

There is an investment that returned 7.6% while having a 7.4 PE ratio and a risk evaluation of 1. Estimate the return on this investment assuming its 7.4 PE ratio and Risk evaluation of 1. What is the residual compared to the actual 7.6 return? |PE Ratio Risk Return |7.4 1.0 7.6 11.1 1.3 13.0 8.7 1.1 8.9 11.2 1.2 10.9 11.6 1.7 12.1 12.2 1.3 12.8 12.5 1.2 11.3 12.5 1.3 14.1 13.0 1.6 14.8 13.4 1.4 16.7

PLEASE SHOW STEPS AND BASIC FORMULAS USED FOR EQUATIONS AND CALCULATIONS.PREVIOUS CHEGG ANSWER CANNOT BE COMPREHENDED.

use coulombs law to calculate the ionization energy in kj mol^-1 of an atom composed of a proton and an electron separated by 249 pm.

E ionization =

the formula we have states (E coulomb approx equals q1q2/r12 ?