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Zorluk: OrtaDirect, Inverse, Joint and Partial Variation

The pressure PP of a given mass of gas varies directly as its absolute temperature TT and inversely as its volume VV. Given that P=50 kPaP = 50\text{ kPa} when T=300 KT = 300\text{ K} and V=10 m3V = 10\text{ m}^3, what is the value of PP when T=360 KT = 360\text{ K} and V=8 m3V = 8\text{ m}^3?

  1. A
    48 kPa48\text{ kPa}
  2. B
    60 kPa60\text{ kPa}
  3. 75 kPa75\text{ kPa}Cevap
  4. D
    90 kPa90\text{ kPa}

Cevap

75 kPa75\text{ kPa}
The relationship is governed by P=kTVP = \frac{kT}{V}. Substituting P=50P = 50, T=300T = 300, and V=10V = 10 yields k=53k = \frac{5}{3}. Using k=53k = \frac{5}{3} with T=360T = 360 and V=8V = 8 gives P=(5/3)×3608=75 kPaP = \frac{(5/3) \times 360}{8} = 75\text{ kPa}.

Adım Adım Çözüm

1
Set up the general formula for joint and inverse variation.
P=kTVP = \frac{kT}{V}, where kk is the constant of variation.
Pressure varies directly as temperature TT and inversely as volume VV.
2
Substitute initial conditions to determine kk.
50=k×30010    50=30k    k=5350 = \frac{k \times 300}{10} \implies 50 = 30k \implies k = \frac{5}{3}.
The initial values P=50 kPaP = 50\text{ kPa}, T=300 KT = 300\text{ K}, and V=10 m3V = 10\text{ m}^3 allow solving for kk.
3
Calculate the new pressure with updated temperature and volume values.
P=53×3608=6008=75 kPaP = \frac{\frac{5}{3} \times 360}{8} = \frac{600}{8} = 75\text{ kPa}.
Substitute k=53k = \frac{5}{3}, T=360 KT = 360\text{ K}, and V=8 m3V = 8\text{ m}^3 into the variation formula.

Anahtar Kavram

Joint and inverse variation in algebraic relationships
Tahmini Süre:1m 30s
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