a) Consider a person of 70 Kg. 0.20% of the body mass is potassium and it...

a) Consider a person of 70 Kg. 0.20% of the body mass is potassium and it is a vital nutrient. Natural potassium (mostly ³⁹K and ⁴¹K) also contains 0.012% ⁴⁰K with a half- life time of 1.3 billion years. ⁴⁰K emits a β- of average energy of 58.5 keV in 89.3% of its decays and a 1.461 MeV γ-ray in 10.7% of the decays. How many of these high-energy γ-rays is generated in the person per second?

b) If you assume that all the energy from the electrons and γ-rays is absorbed in the body, what is the effective dose for the person in one year?

c) While nowadays 0.012% of all potassium is ⁴⁰K, what was its share of all potassium 4.5 billion years ago, when the Earth formed?

Expert Solution

gladiator answered 1 year ago

A person with mass mp = 70 kg stands on a spinning platform disk with a...

A person with mass mp = 70 kg stands on a spinning platform disk with a radius of R = 2.1 m and mass md= 187 kg. The disk is initially spinning at ω = 1.4 rad/s. The person then walks 2/3 of the way toward the center of the disk (ending 0.7 m from the center). 1. What is the total moment of inertia of the system about the center of the disk when the person stands on the...

A person with mass m= 70 kg takes the elevator to the top of the Empire...

A person with mass m= 70 kg takes the elevator to the top of the Empire State Building at a height of 300 m. Assum the elevator takes 1 min to reach the top of the building (a) Find the work done on the person by gravity during the elevator ride? (b) Find the amount of work the normal force of the floor did on the person. (c) Find the average power of the force of gravity.

A 70 kg person is parachuting and experiencing a downward acceleration of 1.9 m/s2. The mass...

A 70 kg person is parachuting and experiencing a downward acceleration of 1.9 m/s2. The mass of the parachute is 4.1 kg. (a) What is the upward force on the open parachute from the air? (b) What is the magnitude of the downward force on the parachute from the person?

A: Assume that the mass of a person is 70kG and 8% of the body mass...

A: Assume that the mass of a person is 70kG and 8% of the body mass is blood. If the density of blood is 1.055g/mL, what is the blood volume? B: Assume that the hematocrit (the ratio of the volume of red blood cells to the total volume of blood) ratio is 0.45, what is the plasma volume of this person? C: Assume that the average life span of the red blood cell is 120 days. What volume of red...

The human body contains 0.20% natural potassium. K-40 represents 0.0117% of naturally occurring potassium. 1. What...

The human body contains 0.20% natural potassium. K-40 represents 0.0117% of naturally occurring potassium. 1. What is the radioactivity due to K-40 for a person weighing 70 kg? 2. What is the radioactivity due to K-40 for all people on Erath?

A person with mass m1 = 80 kg person climbs a uniform ladder with mass m2...

A person with mass m1 = 80 kg person climbs a uniform ladder with mass m2 = 40 kg and length L = 10 m long that rests against a vertical frictionless wall at an angle of θ = 70° with the floor. When the person climbs 7.0 m from the base of the ladder, the ladder starts to slip. When answering the questions, use the symbolic notations given before using numerical substitutions. B)Find the force of the wall Fw...

Body Mass = 85.7 kg ISF hyd

Body Mass = 85.7 kg ISF hydrostatic pressure = 1 mmHg Hematocrit = 45% ISF osmotic pressure = 0 mmHg Blood pressure = 117/72 (mmHg) Arteriole end of capillary hydrostatic pressure = 34 mmHg Ejection Fraction = 60% Net Filtration Pressure (arteriole end) = 11 mmHg EDV = 140 ml Net Filtration Pressure (venule end) = -8 mmHg Cardiac Output = 6.3 L/min What is this person’s stroke volume? ___________________ What is this person’s end systolic volume? ___________________ What is...

A mass of 70 kg of 15-wt-% solution of H2SO4 in water at 70 oC is...

A mass of 70 kg of 15-wt-% solution of H2SO4 in water at 70 oC is mixed at atmospheric pressure with 110 kg of 80-wt-% H2SO4 at 38oC. During the process heat in the amount of 20,000 kJ is transferred from the system. Determine the temperature of the product solution

A 0.20 kg mass at the end of a spring oscillates 2.9 times per second with...

A 0.20 kg mass at the end of a spring oscillates 2.9 times per second with an amplitude of 0.14 m . Part A Determine the speed when it passes the equilibrium point. Express your answer to two significant figures and include the appropriate units. vmax = 2.55 ms SubmitMy AnswersGive Up Correct Part B Determine the speed when it is 0.12 m from equilibrium. Express your answer to two significant figures and include the appropriate units. v = SubmitMy...

A disk of mass 2.5 kg and radius 70 cm with a small mass of 0.09...

A disk of mass 2.5 kg and radius 70 cm with a small mass of 0.09 kg attached at the edge is rotating at 1.8 rev/s. The small mass suddenly flies off of the disk. What is the disk's final rotation rate (in rev/s)?

Question