Check the power source. Your thermostat may just not be connected right or at all. A blown fuse, tripped circuit breaker or dead batteries will prevent the thermostat from turning on your furnace.
Dirty thermostat? That’ll cause issues. Clean up any dust, dirt, spider webs and other debris. Any of these things can coat the inside of the thermostat and interfere with both electrical and mechanical functions of the thermostat. Put this on your get-ready-for-winter cleaning list. Just use a soft, clean brush to clean the inside components gently. Don’t get anything wet. Also you can use a can of compressed air, such as is used for electronics, to clear debris.
Check for any loose wires or terminal screws inside the thermostat. Make sure wires aren’t corroded or detached. Never remove the thermostat cover without removing the batteries or turning off the power at the fuse or breaker box. Tighten screws and secure loose wires if needed.
It may be time to replace your thermostat is it’s old. They aren’t meant to last forever and an old thermostat may be costing you a lot of money in wasted energy and time spent tinkering with an outdated model. There are great programmable thermostats available now that are easy to use and simple to connect to your existing HVAC system. Click here for more info on programmable thermostats.
The addition of vectors involve both magnitude and direction. In this case, we make use of a triangle to visualize the problem. The length of two sides were given while the measure of the angle between the two sides can be derived. We then assign variables for each of the given quantities.
Let:
b = length of one side = 8 m
c = length of one side = 6 m
A = angle between b and c = 90°-25° = 75°
We then use the cosine law to find the length of the unknown side. The cosine law results to the formula: a^2 = b^2 + c^2 -2*b*c*cos(A). Substituting the values, we then have: a = sqrt[(8)^2 + (6)^2 -2(8)(6)cos(75°)]. Finally, we have a = 8.6691 m.
Next, we make use of the sine law to get the angle, B, which is opposite to the side B. The sine law results to the formula: sin(A)/a = sin(B)/b and consequently, sin(75)/8.6691 = sin(B)/8. We then get B = 63.0464°. However, the direction of the resultant vector is given by the angle Θ which is Θ = 90° - 63.0464° = 26.9536°.
In summary, the resultant vector has a magnitude of 8.6691 m and it makes an angle equal to 26.9536° with the x-axis.
<span>118 C
The Clausius-Clapeyron equation is useful in calculating the boiling point of a liquid at various pressures. It is:
Tb = 1/(1/T0 - R ln(P/P0)/Hvap)
where
Tb = Temperature boiling
R = Ideal Gas Constant (8.3144598 J/(K*mol) )
P = Pressure of interest
Hvap = Heat of vaporization of the liquid
T0, P0 = Temperature and pressure at a known point.
The temperatures are absolute temperatures.
We know that water boils at 100C at 14.7 psi. Yes, it's ugly to be mixing metric and imperial units like that. But since we're only interested in relative pressure differences, it's safe enough. So
P0 = 14.7
P = 14.7 + 12.3 = 27
T0 = 100 + 273.15 = 373.15
And for water, the heat of vaporization per mole is 40660 J/mol
Let's substitute the known values and calculate.
Tb = 1/(1/T0 - R ln(P/P0)/Hvap)
Tb = 1/(1/373.15 K - 8.3144598 J/(K*mol) ln(27/14.7)/40660 J/mol)
Tb = 1/(0.002679887 1/K - 8.3144598 1/K ln(1.836734694)/40660)
Tb = 1/(0.002679887 1/K - 8.3144598 1/K 0.607989372/40660)
Tb = 1/(0.002679887 1/K - 5.055103194 1/K /40660)
Tb = 1/(0.002679887 1/K - 0.000124326 1/K)
Tb = 1/(0.002555561 1/K)
Tb = 391.3034763 K
Tb = 391.3034763 K - 273.15
Tb = 118.1534763 C
Rounding to 3 significant figures gives 118 C</span>
<span>We can use an equation to find the gravitational force exerted on the HST.
F = GMm / r^2
G is the gravitational constant
M is the mass of the Earth
m is the mass of the HST
r is the distance to the center of the Earth
This force F provides the centripetal force for the HST to move in a circle. The equation we use for circular motion is:
F = mv^2 / r
m is the mass of the HST
v is the tangential speed
r is the distance to the center of the Earth
Now we can equate these two equations to find v.
mv^2 / r = GMm / r^2
v^2 = GM / r
v = sqrt{GM / r }
v = sqrt{(6.67 x 10^{-11})(5.97 x 10^{24}) / 6,949,000 m}
v = 7570 m/s which is equal to 7.570 km/s
HST's tangential speed is 7570 m/s or 7.570 km/s</span>
