Halflife is the time taken by a radioactive substance by half its original mass. In this case the half life of the substance is 3 hours.
Therefore; New mass = Original mass × (1/2)^n where n is the number of half lives. In this case, the half life is 3 hours and therefore; the number of half lives in 6 hours will be two.
= if the original mass is 100%
new mass = 100 × (1/2)^2
= 100 × 1/4 = 25%
The remaining mass will be 1/4 of the original mass, meaning a fraction of 3/4 of the initial mass will have decayed.
Thus; the answer is 3/4
Answer:

Explanation:
1) The moment of inertia of the grindstone is:



Answer:
the walia ibex
Explanation:
i failed a quiz it sayed i hope it helps;)
Tension is the force causing the path. It is always directed inward for circular motion. To hit the ceiling you need B. The stopper will travel along the tangent line it was moving when released (when tension goes to 0). This is upward in B so it will keep going up to the ceiling.
The velocity is pointed along the tangent line at all times (parallel to the edge of the circle at any point)
Answer:
69.69 g
Explanation:
Evaporation of water will take out latent heat of vaporization. Let the mass of water be m and latent heat of vaporization of water be 2260000 J per kg
Heat taken up by evaporating water
= 2260000 x m J
Heat lost by body
= mass x specific heat of body x drop in temperature
60 x 3500 x .750 ( specific heat of human body is 3.5 kJ/kg.k)
= 157500 J
Heat loss = heat gain
2260000 m= 157500
m = .06969 kg
= 69.69 g