Answer:
10. B
13. It's actually 30 seconds but 20 comes closest so B
14. B, any type of stretching is good before you perform any type of physical activity because it loosens up the muscles
15. D, all of the above
Explanation:
I have done many sports in my life and am still very active, I grew to know most of these things through the years.
Answer:
Doubling the voltage in this arrangement both doubles the voltage drop across the resistor and the current through it. The bulb will be much brighter.
Sound waves can be used in a similar way to "see" things. After turning on a sound source, we can look at the pattern of reflected sound waves that bounce back to us. Our own ears and brain don't process sound into mental pictures.
Answer:
The thermal conductivity of the wall = 40W/m.C
h = 10 W/m^2.C
Explanation:
The heat conduction equation is given by:
d^2T/ dx^2 + egen/ K = 0
The thermal conductivity of the wall can be calculated using:
K = egen/ 2a = 800/2×10
K = 800/20 = 40W/m.C
Applying energy balance at the wall surface
"qL = "qconv
-K = (dT/dx)L = h (TL - Tinfinity)
The convention heat transfer coefficient will be:
h = -k × (-2aL)/ (TL - Tinfinty)
h = ( 2× 40 × 10 × 0.05) / (30-26)
h = 40/4 = 10W/m^2.C
From the given temperature distribution
t(x) = 10 (L^2-X^2) + 30 = 30°
T(L) = ( L^2- L^2) + 30 = 30°
dT/ dx = -2aL
d^2T/ dx^2 = - 2a
