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3 years ago

HELP WILL GIVE BRAINLIEST OF CORRECT

Physics

2 answers:

stepladder [879]3 years ago

7 0

It’s D. because it’s velocity is changing

wel3 years ago

5 0

Answer:

Explanation:

The answer is B)- The object's speed must be changing.

So will I get the Brainliest...

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Our Sun is considered a(n) _____ star. A. small B. large C. giant D. average

faltersainse [42]

Checking a table of star sizes, we'll see that our Sun is a medium sized star, so the answer is D, average.

5 0

3 years ago

Definition: A command economy is where a central government makes all economic decisions. The government or a collective owns th

denis-greek [22]

A command economy is a system where the government, rather than the free market, determines what goods should be produced, how much should be produced and the price at which the goods are offered for sale.

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3 years ago

Air at 80 kPa and 127 °C enters an adiabatic diffuser steadily at a rate of 6000 kg/h and leaves at 100 kPa. The velocity of the

Vinil7 [7]

Answer:

a) The exit temperature is 430 K

b) The inlet and exit areas are 0.0096 m² and 0.051 m²

Explanation:

a) Given:

T₁ = 127°C = 400 K

At 400 K, h₁ = 400.98 kJ/kg (ideal gas properties table)

The energy equation is:

$q-w=h_{2} -h_{1} +\frac{V_{2}^{2}-V_{1}^{2} }{2} +delta-p$

For a diffuser, w = Δp = 0

The diffuser is adiabatic, q = 0

Replacing:

$0-0=h_{2} -h_{1} +\frac{V_{2}^{2}-V_{1}^{2} }{2} +0$

Where

V₁ = 250 m/s

V₂ = 40 m/s

Replacing:

$0-0=h_{2} -400x10^{3} +\frac{40^{2}-250^{2} }{2} +0\\h_{2} =431430 J/kg=431.43kJ/kg$

Using tables, at 431.43 kJ/kg the temperature is 430 K

b) The inlet area is:

$m=\frac{P_{1} }{RT_{1} } A_{1} V_{1} \\\frac{6000}{3600} =\frac{80}{0.287*400} A_{1} *250\\A_{1} =0.0096m^{2}$

The exit area is:

$m=\frac{P_{2} }{RT_{2} } A_{2} V_{2} \\\frac{6000}{3600} =\frac{100}{0.287*430} A_{2} *40\\A_{2} =0.051m^{2}$

6 0

3 years ago

a disk initially at rest rotates with constant angular acceleration through an angel of 50 rad in 5 sec find the angular speed o

lisov135 [29]

Recall the formula,

∆θ = ω₀ t + 1/2 α t ²

where ∆θ = angular displacement, ω₀ = initial angular speed (which is zero because the disk starts at rest), α = angular acceleration, and t = time. Solve for the acceleration with the given information:

50 rad = 1/2 α (5 s)²

α = (100 rad) / (25 s²)

α = 4 rad/s²

Now find the angular speed ω after 3 s using the formula,

ω = ω₀ + α t

ω = (4 rad/s²) (3 s)

ω = 12 rad/s

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3 years ago

A heat engine has a maximum possible efficiency of 0.780. If it operates between a deep lake with a constant temperature of-24.8

Volgvan

Answer : The temperature of the hot reservoir (in Kelvins) is 1128.18 K

Explanation :

Efficiency of carnot heat engine : It is the ratio of work done by the system to the system to the amount of heat transferred to the system at the higher temperature.

Formula used for efficiency of the heat engine.

$\eta =1-\frac{T_c}{T_h}$