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A ball with radius 10cm is filled with an ideal gas at pressure 2*(10)^5Pa and temperature 300K. The volume of the gas is changed at constant pressure so that the radius of the ball is reduced with 1cm. Find the amount of gas and the new temperature

In a question like this, you will be given that the molar gas constant is R = 8.31JK -1 mol -1 . However, committing this to memory will be helpful. We should use the ideal gas law: PV = nRT but the volume o...
IG
Answered by Ivan G. • Physics tutor
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A Positron has the same mass, but opposite charge to an electron. A Positron and electron are orbiting around each other separated by 1μm, in a stable circular orbit about their centre of mass, as a result of electrostatic attraction. Calculate the period

State Coulomb's law:F=(1/4πE 0 ) (qQ/d 2 )Since the distance separating the charges is twice the radius of the orbit relabel d to 2r and the charges are equal and opposite:F= -(1/16πƐ 0 ) (q/r) 2 Notice that...
JB
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An elastic wire suspended from a workbench has a 2kg mass attached to its free end. The wire changes in length by 2cm. Calculate the elastic potential energy stored in the wire.

Using Hooke's law (F = k * e) we can find the spring constant. Rearranging for k, we find that k = (9.81 * 2)/0.02 = 981 N/m. To calculate this we needed to find the force acting on the wire (F = mg) and als...
JG
Answered by James G. • Physics tutor
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What is an atom?

It is composed of Protons, Neutrons and Electrons. The Proton is positively charged and is present in the central nucleus part of the atom.The Neutron has no charge and also is present in the nucleusThe Elec...
SB
Answered by Sam B. • Physics tutor
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the moon takes 27.3 days (2.36x10^6s) to orbit the earth . Calculate its distance from the earth . Take the mass of the earth to be 5.975x10^24kg.

Use the set formula T 2 =(4Pi^2/GM)R^3 and rearrange for r^3 to give r 3 = T 2 GM/ 4Pi 2 then insert values : r 3 = (2.36x10 6 ) 2 x 6.67x10 -11 x 5.975x10 24 / 4PI 2 = 5.62....x10 25 Then take the cube root...
Answered by • Physics tutor
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