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In the Pacific, MacArthur and the Allied forces pursued an island hopping strategy that bypassed certain island strongholds held by the Japanese that were of little or no strategic value. By seizing locations from which Japanese communications and transportation routes could be disrupted or destroyed, the Allies advanced towards Japan without engaging the thousands of Japanese stationed on garrisoned islands. The goal was to advance American air strength close enough to Japan proper to achieve air superiority over the home islands; the nation could then be bombed into submission or at least weakened in preparation for an amphibious assault. By February 1945, American forces had reached the island of Iwo Jima ( [link] ). Iwo Jima was originally meant to serve as a forward air base for fighter planes, providing cover for long-distance bombing raids on Japan. Two months later, an even larger engagement, the hardest fought and bloodiest battle of the Pacific theater, took place as American forces invaded Okinawa. The battle raged from April 1945 well into July 1945; the island was finally secured at the cost of seventeen thousand American soldiers killed and thirty-six thousand wounded. Japanese forces lost over 100,000 troops. Perhaps as many as 150,000 civilians perished as well.

A photograph shows American forces arriving ashore on the dark sands of Iwo Jima. Mount Suribachi is visible in the background.
American forces come ashore on Iwo Jima. Their vehicles had difficulty moving on the beach’s volcanic sands. Troops endured shelling by Japanese troops on Mount Suribachi, the mountain in the background.

Dropping the atomic bomb

All belligerents in World War II sought to develop powerful and devastating weaponry. As early as 1939, German scientists had discovered how to split uranium atoms, the technology that would ultimately allow for the creation of the atomic bomb. Albert Einstein, who had emigrated to the United States in 1933 to escape the Nazis, urged President Roosevelt to launch an American atomic research project, and Roosevelt agreed to do so, with reservations. In late 1941, the program received its code name: the Manhattan Project    . Located at Los Alamos, New Mexico, the Manhattan Project ultimately employed 150,000 people and cost some $2 billion. In July 1945, the project’s scientists successfully tested the first atomic bomb.

In the spring of 1945, the military began to prepare for the possible use of an atomic bomb by choosing appropriate targets. Suspecting that the immediate bomb blast would extend over one mile and secondary effects would include fire damage, a compact city of significant military value with densely built frame buildings seemed to be the best target. Eventually, the city of Hiroshima, the headquarters of the Japanese Second Army, and the communications and supply hub for all of southern Japan, was chosen. The city of Kokura was chosen as the primary target of the second bomb, and Nagasaki, an industrial center producing war materiel and the largest seaport in southern Japan, was selected as a secondary target.

The Enola Gay    , a B-29 bomber named after its pilot’s mother, dropped an atomic bomb known as “Little Boy” on Hiroshima at 8:15 a.m. Monday morning, August 6, 1945. A huge mushroom cloud rose above the city. Survivors sitting down for breakfast or preparing to go to school recalled seeing a bright light and then being blown across the room. The immense heat of the blast melted stone and metal, and ignited fires throughout the city. One man later recalled watching his mother and brother burn to death as fire consumed their home. A female survivor, a child at the time of the attack, remembered finding the body of her mother, which had been reduced to ashes and fell apart as she touched it. Two-thirds of the buildings in Hiroshima were destroyed. Within an hour after the bombing, radioactive “black rain” began to fall. Approximately seventy thousand people died in the original blast. The same number would later die of radiation poisoning. When Japan refused to surrender, a second atomic bomb, named Fat Man, was dropped on Nagasaki on August 9, 1945. At least sixty thousand people were killed at Nagasaki. Kokura, the primary target, had been shrouded in clouds on that morning and thus had escaped destruction. It is impossible to say with certainty how many died in the two attacks; the heat of the bomb blasts incinerated or vaporized many of the victims ( [link] ).

Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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Source:  OpenStax, U.s. history. OpenStax CNX. Jan 12, 2015 Download for free at http://legacy.cnx.org/content/col11740/1.3
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