7. Determine the gradient and the y-intercept of this equation if plotted as stated.
[2]
8. Dinara blows into one arm of a manometer. (сурет)The difference in the levels of the water in the two arms of the manometer is found to be 90 cm. What is the total pressure exerted by her blowing? Density of water is 1 g−3 , atmospheric pressure is Po = 1.01 x 105 Pa and g = 10N/kg.
[2]
9. A pipe of uniform cross-sectional area of 1.0 x 10−4 m2 and length 5.0 x 10-1 m lets in water from one end to the other in 5 seconds. Calculate the rate of flow of the water.
[2]
10. A lawn sprinkler with 40 holes each of uniform cross-sectional area 4.0 x 10-2 cm2 is connected to a hosepipe of cross-sectional area 4.8cm-2. If the speed of water in the hosepipe is 3.0 cms-1, determine the speed as it emerges from the holes.
[2]
11. Calculate the magnitude of the resultant force in the case below.
193
Объяснение:
Тепловой баланс: Q₁=Q₂,
Q₁ - количество теплоты, которую забрал сосуд, вода и лёд;
Q₂ - количество теплоты, которая выделилась после конденсации пара и охлаждения воды.
сΔt₁ - нагрев сосуда, где Δt₁=6°C-0°C=6°C.
c₁m₁Δt₁ - нагрев воды, где с₁=4200 Дж/кг·°С; m₁=2 л.
λm₂ - плавление льда, где λ=330000 Дж/кг; m₂=1,3 кг.
с₁m₂Δt₁ - нагрев получившейся воды.
Q₁=сΔt₁+c₁m₁Δt₁+λm₂+с₁m₂Δt₁=184·6+4200·2·6+330000·1,3+4200·1,3·6=1104+50400+429000+32760=513264 Дж
Lm₃ - парообразование, где m₃ - масса пара.
с₁m₃Δt₂ - охлаждение воды, где Δt₂=100°C-6°C=94°C.
Q₂=Lm₃+с₁m₃Δt₂=m₃(L+c₁Δt₂)
513264=m₃(2260000+4200·94)
m₃=513264/2654800
m₃≈0,193 кг ≈ 193 г