Odpowiedzi

Najlepsza Odpowiedź!
2010-03-24T12:16:11+01:00
7.
---

-------------------------------------------------------

10.
m = 0.1 kg
c = 130
v₁=200m/s
v₂=100m/s
Ek = mv²/2
Ek1 = 0,1 x 200²/2 = 0,1 x 40000/2 = 2000 J
Ek2 = 0,1 x 100²/2 = 0,1 x 10000/2 = 500J
ΔEk= 1500 J
½Ek = Ew
Ew = 1500/2 = 750 J

Q = cmΔT
Q = Ew

750 = 130 x 0,1 x Δt
750 = 13ΔT
ΔT = 750/13
ΔT = 57,7°C

Pocisk ogrzał się o 57,7°C.

-------------------------------------------------------

13.
M=10kg
Cw=4200J/kg°C
Cal=896J/kg°C
T2=150 °C
T1=10 °C
m=?
T=11°C

Q₁=Q₂
m*Cal*(T₂-T)=M*Cw*(T-T₁)
m=[M*Cw*(T-T₁)]/[Cal*(T₂-T)]

m=10*4200*1/896*139=42000/124544=0,34kg

Odp. Masa bryły to 0,34kg.

-------------------------------------------------------

15.

P=50kW=50000W
t=6h=6*3600s=21600s

P=W/t
W=P*t=21600*50000=1080 000 000 J=1080 MJ

1 litr----W'
x litrów --W

1 litr----50 MJ
x litrów --1080 MJ

x litrów =21,6 litra

Odp. Spali 21,6 l benzyny.

-------------------------------------------------------

16.

E=W=100kJ=100000J
P=200W

P=W/t
t=W/P=100000J/200W=500s=8 min 20s

Odp. W czasie 8min i 20s.

-------------------------------------------------------

18.

T₁=20°C
T₂=90°C
T=30°C

m₁/m₂=?

Q₁=Q2

Q₁=m₁*Cw*(T-T₁)
Q2=m₂*Cw*(T₂-T)

m₁*Cw*(T-T₁)=m₂*Cw*(T₂-T)

m₁/m₂=[(T₂-T)]/[(T-T₁)]=60/10=6

m₁=6*m₂

Odp. 6:1 .

-------------------------------------------------------

19.
Q=m*L=5kg*334kJ/kg=1670 kJ

Odp. Różnica ta wynosi 1670 kJ.

-------------------------------------------------------