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:
I'm pretty sure it's 37.5 joules of energy
Explanation:
hope this helps!
C, N and O all belong to the same period, in which it's 2nd Period.
Answer:
54 N
Explanation:
Draw a free body diagram. There are four forces acting on the balloon. Buoyant force pushing the balloon up, gravity pulling the helium down, gravity pulling the balloon skin down, and gravity pulling the load down.
Apply Newton's second law:
∑F = ma
B − Wh − Wb − L = ma
When the load is at a maximum, the acceleration is 0:
B − Wh − Wb − L = 0
B − Wh − Wb = L
B − mh g − Wb = L
The mass of the helium is its density times its volume:
B − ρh Vh g − Wb = L
Buoyant force is defined as B = ρVg, where ρ is the density of the displaced fluid (in this case, air), V is the volume of the displaced fluid, and g is acceleration of gravity. Since the volume of displaced air = the volume of the helium:
ρa V g − ρh V g − Wb = L
(ρa − ρh) V g − Wb = L
Given that ρa = 0.90 kg/m³, ρh = 0.178 kg/m³, V = 20 m³, g = 9.8 m/s², and Wb = 88 N:
(0.9 − 0.178) (20) (9.8) − (88) = L
L = 53.5 N
Rounded to 2 sig-figs, the maximum load that can be supported is 54 N.
Answer:
66.8°C
Explanation:
dQ = m*cp*dT where:
m = mass of block
cp = specific heat of iron
dT = temperature change
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dQ = 3.5 10^4 J
cp = 0.45 Kj / Kg = 450 J / Kg
3.5 10^4 = 2.3 * 450 * dt-----dt = 35000 / 450 * 2.3 = 33.8 °
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Final temperature = 33 + 33.8 = 66.8 °C
