Answer:
A 1.0 min
Explanation:
The half-life of a radioisotope is defined as the time it takes for the mass of the isotope to halve compared to the initial value.
From the graph in the problem, we see that the initial mass of the isotope at time t=0 is
The half-life of the isotope is the time it takes for half the mass of the sample to decay, so it is the time t at which the mass will be halved:
We see that this occurs at t = 1.0 min, so the half-life of the isotope is exactly 1.0 min.
Answer:
Colour of any object is by the colour of light it reflects i.e if white light is incident on the object,it will reflect blue color.so it will appear blue.But if red light is incident on it,it will not reflect that and absorb it.so as it will not reflect any light it will appear black.
Explanation:
Answer:
Explanation:
a ) Thermal efficiency = work output / heat input
= .38 MW / 1 MW = .38
OR 38%
Heat rejected at cold reservoir = heat input - work output
1 MW - .38 MW
= 0.62 MW.
b ) For reversible power output
efficiency = T₂ - T₁ / T₂ ; T₂ is temperature of hot reservoir and T₁ is temperature of cold reservoir.
= 1200 - 300 / 1200 = 900 / 1200
= .75
or 75%
rate at which heat is rejected
= 1 - .75 x 1
= .25 MW .
<h3>
Answer: 22.5 m/s</h3>
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Work Shown:
acceleration = ( finalVelocity - initialVelocity )/(change in time)
1.5 = (60 - x)/(25)
1.5*25 = 60-x
37.5 = 60-x
x = 60-37.5
x = 22.5
The initial velocity is 22.5 m/s
Answer:
Explanation:
Assuming that velocities remain negligible,
The work will be equal to the change in potential energy of the center of mass
mass is 30 m(5 kg/m) = 150 kg
W = 150(9.8)(30/2) = 22,050 J ≈ 22 kJ
