Recent content by shin777

how about this one? latent heat of fusion(L) = 80 cal g Mc = mass of ice heat gained = (Mc *4180 * 15) + (Mc * L) + (Mc * 4180 * t) heat gained = (30 * 4180 *15) + (30 * 80) + (30 * 4180 * t) t = -15c final temp is -15c

hmm.. my tutor help me to solve this problem but now I look at it again, some of these equation don't make sense. any suggestion? :(

30g of ice at -15 degree celsius is added to 100g of water at 25 degree celsius. What is the final temperature? T1=ice T2=H2O at equilibrium must have m1c1(Te-T1)+m1k=m2c2(T2-Te) [k=3.3x10^5 J/K fusion heat coeff.] then Te=(m1c1T1+m2c2T2-m1k)/(m1c1+m2c2) T1=268 k T2=298 K...

my bad.. i got it now. it's vf = ( 25 + 2(9.8)(50) ) ^ 1/2 vf = 1005^(1/2) vf = 31.7 m/s

err.. yeah.. I think it should have been Vi^2 + gh = (1/2)Vf^2 5^2 + 9.8(50) = (1/2)Vf^2 2(515) = Vf^2 Vf = 32 m/s does it look ok now?

1. What force is needed to pull a 10kg box across a floor that has a coefficient of friction of .34? my answer F = W * f * x F = .34(10)(9.8) = 33N 2. The carts of a roller coaster are traveling 5 m/s over the top of the first hill. If there is no energy loss due to friction and the...

thx. what about question 9? do I need to solve question 8 to figure out question 9?

hmm.. i think it would make 10 look slower and ccw and 11 faster and cw. so #7 is 10.758x4.17 = 44.9 N m.

is it the other way around? I don't have strobescope and wheel in front of me so I can't guess. :( as for #7, do i have to use 4.17 one instead of 5.83 as alpha?

can I get equation for #7 then? 10, I think it would appear to move slower in same direction and 11, it would appear to move faster in opposite direction. I am not really sure. :(

it didn't give friction value for #7 though.. as for 10, I think disk would appear to move slower and , 11 would make disk look move faster?

Thank you. Here are rest of questions. I think I got 6, 7 right but I don't understand from 8 to 11 at all. How do I do these? :( question 6)Find I, the moment of inertia for the color wheel in kg m^2. I = 1/2 mr^2 I = (1/2)(133.4)(12.7^2) I = 10758/1000 = 10.758 kg m^2 question 7)...

oh.. so is it just rev then?

unit for angle is degree but the question is asking it in rev so I converted 56.7 degree to 9 rev by divide it by 2pi.

is it rev/s^2?