A projectile fired upward from the Earth's surface will usually slow down, come momentarily to rest, and return to Earth. For a certain initial speed, however it will move upward forever, with its speed gradually decreasing to zero just as its distance from Earth approaches infinity. The initial speed for this case is called escape velocity. You can find the escape velocity v for the Earth or any other planet from which a projectile might be launched using conservation of energy. The projectile of mass m leaves the surface of the body of mass M and radius R with a kinetic energy Ki = mv²/2 and potential energy Ui = -GMm/R. When the projectile reaches infinity, it has zero potential energy and zero kinetic energy since we are seeking the minimum speed for escape. Thus Uf = 0 and Kf = 0. And from conservation of energy,
Ki + Ui = Kf + Uf
mv²/2 -GMm/R = 0
∴ v = √(2GM/R)
This is the expression for escape velocity.
Answer:
conductivity of solution is reduced.
Explanation:
When two oppositely charged electrodes are immersed in a solution, positively charged ions are attracted to the negative electrode and gain electrons. The negatively charged ions are attracted to the positive electrode and release electrons.
Due to the process mentioned above , the negatively charged ions are accumulated at the positive electrode and the positively charged ions are accumulated at the negative electrode . This accumulation prevents further attraction of ions at oppositely charged electrodes because the incoming ions face repulsion from already accumulated ions at electrodes. Further , it creates an emf acting in opposite direction . It reduces the current through the solution. Hence conductivity of solution is reduced.
Explanation:
Given that,
Voltage of household line, V = 110 V
Power of the hairdryer, P = 1650 W
During use, the current is about 1.95 cm from the user's hand.
(a) Power is given by :
(b) Again the power is given by :
R is resistance of the dryer
(c) The magnetic field produced by the dryer at the user's hand is given by :
Hence, this is the required solution.
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