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  1. J

    Change in Capacitor for largest possible Current

    Homework Statement The capacitor is changed so that the largest possible current is supplied by the source. Enter the value of the capacitive reactance when this change is made. Give your answer in Ohms (Ω). A unit is not required with your answer. Homework Equations The circuit is powered by...
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    Resistance of Patient

    Homework Statement When the defibrillation shock is applied, the capacitor discharges through the patient as shown in the diagram below: The fraction of charge remaining on the capacitor 1.00 ms after it begins discharging is 0.300. Calculate the resistance of the patient. Note: This will...
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    Charge Stored on a Capacitor

    Homework Statement Defibrillation[/B] is a common treatment for life-threatening cardiac arrhythmias and ventricular fibrillation. The defibrillator applies a current across the heart (shown by the red arrows in the image below) for a short time (a few milliseconds), disrupting the arrhythmia...
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    Net Charge on a Magnesium ion

    Homework Statement Calculate the net charge on a magnesium ion which has lost two electrons. 2. The attempt at a solution I put 2+ as my answer and this is what I was told, but I don't understand what they mean by the following; That's a chemist's shorthand, not the amount of charge on the...
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    Image Distance

    Homework Statement You look at yourself in a shiny Christmas tree ball, which has a diameter of 9.63 cm. If your face is 7.81 cm away from the shiny ball, calculate the image distance. Homework Equations ??? Thinking I would use magnification = di/d0 di = 0.0781m d0 = 0.0963m The Attempt at...
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    Plane Mirror - distance

    Homework Statement Suppose that you want to take a mirror selfie, standing 3.05 m in front of a plane mirror. Calculate the distance that the camera will focus to, to get a clearly focused image of your beautiful self. Homework Equations d0 = di The Attempt at a Solution Would I be correct...
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    The Distance to the seabed

    Homework Statement A depth sounder on a ship measures the distance between the bottom of the ship and the seabed using a high-frequency pulse of sound (sonar stands for SOund Navigation And Ranging). Sound travels through water at 1.48 km/s. Calculate the distance to the seabed if the...
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    Time for radio signal to get to a receiver

    Homework Statement A radio transmitter is located 17.5 km away. The broadcast signals travel at the speed of light (c = 3.00 x 108 m.s-1) through the air towards a radio receiver. Calculate the time it takes the radio signal to travel from the transmitter to the receiver. Homework Equations...
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    Thermodynamics - Hypothermia - Heat loss

    Homework Statement A careless farmer sends this sheep out to graze on a very cold winter day when the temperature is -10oC. The sheep's coat has a thickness of 4.7 cm and a surface area 1.3 m2. Calculate the rate of heat loss from the sheep on this cold day. Assume that heat is lost only...
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    Simple Harmonic Motion - rearranging equation

    Homework Statement How to rearrange following equation? Homework Equations f = (1/2pi) square root of (k/m) The Attempt at a Solution (f^2 x m)/ (1/2pi)^2 Is this how i would do it?
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    Simple Harmonic Motion - Speed

    Homework Statement Calculate the speed of the block in SHM as it moves through equilibrium position. k= 45.08248265 N/m m of block = 0.505kg T = 0.665s Homework Equations w= the square root of (k/m) ??? The Attempt at a Solution w = the square root of (45.08248265/0.505) = 9.448398958 =...
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    Thermodynamics: Dropping a hot horseshoe into a pot of water

    Homework Statement A freshly-forged iron horseshoe, with a mass of 0.549 kg is dropped into a 0.281 kg iron pot which contains 1.60 kg of water at 21.4 oC. After the horseshoe, pot and water reach thermal equilibrium they have a temperature of 29.8 oC. Assuming the pot and the water were in...
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    Thermodynamics - Change in Temp

    Homework Statement A 77.1 kg hiker uses 191 kcal hr-1 (converted to 222.133 J.s ????) of energy whilst hiking. Assuming that 20% of this energy goes into useful work and the other 80% is converted to heat within the body, calculate the temperature change, in units of Kelvin (K), of the hiker's...