The answer is b no problem
W=20 e(-kt)
A. Rearranging gives k= -(ln(w/20)/t
Substituting w= 10 and solving gives k=0.014
B. Using W=20e(-kt). After 0 hours, W=20. After 24 hours, W=14.29g. After 1 week (24x7=168h) W=1.9g
C. Rearranging gives t=-(ln(10/20)/k. Substituting w=1 and solving gives t=214 hours.
D. Differentiating gives dW/ dt = -20ke(-kt). Solving for t=100 gives dW/dt = 0.07g/h. Solving for t=1000 gives 0.0000002g/h
E. dW/dt = -20ke(-kt). But W=20e(-kt) so dW/dt = -kW
Answer:

Explanation:
Let the linear charge density of the charged wire is given as

here we can use Gauss law to find the electric field at a distance r from wire
so here we will assume a Gaussian surface of cylinder shape around the wire
so we have

here we have


so we have

Answer:
Explanation:
a ) AM radio band (540–1600 kHz)
frequency = 540 kHz = 540 x 10³ Hz
wave length = velocity of light / frequency
= 3 x 10⁸ / 540 x 10³
= 555.55 m
frequency = 1600 kHz = 1600 x 10³ Hz
wave length = velocity of light / frequency
= 3 x 10⁸ / 1600 x 10³
= 187.5 m
maximum wavelength = 555.55 m
minimum wavelength = 187.5 m
b )
AM radio band (88 - 108 MHz)
frequency = 88 MHz = 88 x 10⁶ Hz
wave length = velocity of light / frequency
= 3 x 10⁸ / 88 x 10⁶
= 3.41 m
frequency = 108 MHz = 108 x 10⁶ Hz
wave length = velocity of light / frequency
= 3 x 10⁸ / 108 x 10⁶
= 2.78 m
maximum wavelength = 3.41 m
minimum wavelength = 2.78 m
Answer: A little more that 5 Kg for a healthy person
Explanation: First, we know the following:
The regular adult has from 9 to 12 pints of blood. This is around 5 liters for a healthy male adult.
The human body is composed mostly on water, around 80%.
Blood is mostly composed on plasma, which makes blood thicker than water.
Knowing that, almost all the body is compose of water, it is safe to think that blood density should be near to that of water but higher.
The density on water is a know value. Which makes the following true:
<em>1 Liter of Water weights 1 Kg</em>
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It could be said then, that the total mass of blood for a healthy person should be a little more that 5 kgs.