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:
a ) The earth rotates by 2π radian in 24 x 60 x 60 s
so angular speed ( w ) = 2π / (24 x 60 x 60) = 7.268 x 10⁻⁵ rad / s
b ) Linear speed of city of Arlington ( v ) = w r = w R Cosλ where R is radius of the earth and λ is latitude .
v = 7.268 x 10⁻⁵ x 6.371 x 10⁶ cos 32.7357
389.5 m /s
acceleration = w² r = w² R Cos 32.7357
= (7.268 x 10⁻⁵ )² x 6.371 x 10⁶ x cos 32.7357
=283.08 x 10⁻⁴ m/s²
c) velocity ratio =
w r /w R =
R cos 32.73/ R
= Cos 32.73
= 0.84 .
A man inside an insulated metallic cage does not receive shock when the cage is highly charged because the whole charge reside on outer surface of the cage.
If the cage was a non-conductive cage, then the current cannot pass through the cage so it cannot affect the person in the cage.
For example- If you are seated in a car (metal body) and the car is hit with lightning, it is very unlikely that the person in the car would be hit with the lightning.
Answer:
Geocentric theory: Earth is the center of the universe.
Heliocentric theory: The Sun is the center of the universe.
Explanation:
The geocentric theory was formulated by Aristotle and says that the earth is the center of the universe and the other planets and stars including the sun revolve around it.
On the other hand, Copernicus with his heliocentric theory states that the sun is the center of the universe and the planets revolve around it.