Answer:
minimum length of a surface crack is 18.3 mm
Explanation:
Given data
plane strain fracture toughness K = 82.4 MPa m1/2
stress σ = 345 MPa
Y = 1
to find out
the minimum length of a surface crack
solution
we will calculate length by this formula
length = 1/π ( K / σ Y)²
put all value
length = 1/π ( K / σ Y)²
length = 1/π ( 82.4 
/ 345× 1)²
length = 18.3 mm
minimum length of a surface crack is 18.3 mm
Answer:
The excess charge on earth's surface was calculated to be 4.56 × 10⁵ C
Explanation:
Using the formula for an electric field;
E = kQ/r²
k = 1/(4πε₀) = 8.99 × 10⁹ Nm²/C²
E = 100N/C
r = radius of the earth = 6400 km = 6400000m
Q = Er²/k = 100 × (6400000)²/(8.99 × 10⁹)
Q = 455617.4 C = 4.56 × 10⁵ C
Hope this helps!!!
Most geologists accept radiometric dating techniques as valid because radioactive elements decay at a constant and measurable rate.
Answer: Option C
<u>Explanation:</u>
Scientists prefer radioactive dating to carbon dating because it is more accurate in measuring. The analysis depends upon the radioactive decay of radioactive isotopes of any matter in a given rock or soil.
The parent atoms and daughter atoms are compared while studying, and hence age can be calculated easily. Radioactive decay depends upon the given half-life of the atom, which is a constant and is known. So, it would be very easy to calculate the number of progeny atoms and parent atoms and find out their age.
<span>3933 watts
At 100 C (boiling point of water), it's density is 0.9584 g/cm^3. The volume of water lost is pi * 12.5^2 * 10 = 4908.738521 cm^3
The mass of water boiled off is 4908.738521 * 0.9584 = 4704.534999 grams.
Rounding to 4 significant figures gives me 4705 grams of water.
The heat of vaporization for water is 2257 J/g. So the total energy applied is
2257 J/g * 4705 g = 10619185 J
Now we need to divide that by how many seconds we've spent boiling water. That would be 45 * 60 = 2700 seconds.
Finally, the rate of heat transfer in Joules per second will be the total number of joules divided by the total number of seconds. So
10619185 J / 2700 s = 3933 J/s = 3933 (kg m^2/s^2)/s = 3933 (kg m^2/s^3)
= 3933 watts</span>
