Recent content by Julia Coggins

To find the y component and then calculate the real distance traveled up the incline. I used sin(20) to find the vertical distance, then used trig to get the whole distance traveled. Managed to account for those missing three meters using significant figured, all is resolved. Thanks to everyone

In the equation to get time, I meant 9.8sin20 not 9.8. I can do so, and it makes sense, but looking at the calculation I fail to understand why I got 137 not 134. Perhaps they used significant figures to round the numbers?

I redid my calculations, reaching 137m instead of 134. I used 30sin20 to find the distance of y it coasts and to stay consistent with the acceleration I used, 9.81sin(20), then used trig to find the real distance. 0=30sin(20) + (-9.81)t t=3.058 y=30sin20(3.058) + 1/2 (9.8sin20)(3.058^2) y=...

Homework Statement A car traveling at 30 m/s runs out of gas whiles traveling up a 20 degree slope. How far up the hill will it coast before staring to roll back down? Vf=0 Vo= 30sin20 a = -9.8sin(20) Homework Equations y=yo + Vo(t) + aT^2 vf=vo+at Vf^2=Vi^2 + 2aY The Attempt at a Solution I...

Unfortunately I don't have wolfram alpha pro, I do need to brush up on my calc though. Isn't l'hospital's rules dealing with indefinite integrals like this one?

Reading it now. I don't understand how they evaluated that integral?

From "Physics for Scientists and Engineers" by Randall D. Knight page 1006. A 1 m long, 1.0 mm diameter nichrome heater wire is connected to a 12 V battery. Find the magnetic field strength 1 cm away from the wire. This problem is solved in the book, but they calculate the magnetic field with...

Yes, thanks all

I know the real and imaginary parts, I just don't know how to show they're equal to cos{a + b} and sin{a+b} respectively.

I'm just not sure how to put this in an equation that has sin(a + b) on one side or cos(a+b)

How do you get cos{a+b}=cos{a}cos{b} - sin{a}sin{b} from cos{a}cos{b} - sin{a}sin{b} + i(sin{a}cos{b} + cos{a}sin{b}? From trying to use Euler's formula. cos{a+b} + isin{a+b} = e^i(a+b)= e^ia + e^ib (cos{a} + isin{a})(cos{b} + isin{b})

So e^x=1+x+x^2/2!+x^3/3!...continues to infinity Replacing x with ix 1+ix-x^2/2! - ix^3/3!...continues to infinity separating the real terms from the imaginary: 1-x^2/2!+x^4/4! - x^6/6! factor out i in the imaginary terms i(x-x^3/3!+x^5/5!-x^7/7!) The real terms match up exactly with the...

So that's an inherent fact? Planck radiation depends on the temperature of the body, so for example at room temperature a body emits infared radiation and cannot be seen. Whereas at the surface of the sun, it emits visible light as well. I guess Planck radiation is inherently the limit, but...

Why is Planck radiation the greatest amount of radiation that anybody at thermal equilibrium can emit from its surface, whatever its chemical composition or surface structure?

Ah I see. Once again, thank you, I suppose for some reason I struggled with an otherwise simple question.