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3 years ago

5

Which of the following statements best explains how heat flows by convection?

2 answers:

AveGali [126]3 years ago

6 0

It is D for sure!!!!

adell [148]3 years ago

5 0

The answer should be C

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If a toy car with a coin on top of it is rolling down a hill what force is keeping the coin on top of the car?

forsale [732]

The answer is gravity.

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3 years ago

How big is the universe?<br> sorry this is so random

prisoha [69]

Answer:

Explanation: 46 billion light years I think

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3 years ago

For a particular casting setup, the top of the sprue has a diameter of 0.030 m, and its length is 0.200 m. The volume flow rate

faust18 [17]

Answer with Explanation:

We are given that

Diameter=0.030 m

Length of sprue= $h_1$ =0.200 m

Metal volume flow rate,Q=0.03 $m^3/min$

Q= $\frac{0.03}{60}=5\times 10^{-4}m^3/s$ because 1 minute=60 seconds

Let 1 for the top and 2 for the bottom

$d_=0.030 m$

$h_2=0$

$A_1=\frac{\pi d^2}{4}=\frac{3.14\times (0.030)^2}{4}$

$A_1=7.065\times 10^{-4} m^2$

$v_1=\frac{Q}{A_1}=\frac{5\times 10^{-4}}{7.065\times 10^{-4}}$

$v_1=0.708 m/s$

Pressure at the top and bottom of the sprue is atmospheric

$h_1+\frac{v^2_1}{2g}=h_2+\frac{v^2_2}{2g}$

Substitute the values

$0.2+\frac{(0.708)^2}{2\cdot 9.8}=0+\frac[v^2_2}{2\cdot 9.8}$

$v^2_2=2\cdot 9.8\cdot \frac{0.2\cdot 9.8\cdot 2+0.501264}{2\cdot 9.8}=4.421264$

$v_2=\sqrt{4.421264}=2.1 m/s$

$Q=A_2v_2$

$5\times 10^{-4}=A_2\times 2.1$

$A_2=\frac{5\times 10^{-4}}{2.1}=2.381\times 10^{-4} m^2$

Reynolds number= $\frac{v_2D\rho}{\eta}$

$\eta=0.004 N.s/m^2$

$\rho=2700 kg/m^3$

Substitute the values then we get

Reynolds number= $\frac{2.1\times 0.03\times 2700}{0.004}$

Reynolds number=42525

The Reynolds number is greater than 4000 .Therefore, the flow is turbulent.

8 0

3 years ago

Which equation would you use to calculate how much work is done in pushing a rock to the edge of the cliff?

Natalka [10]

Answer:

d

Explanation:

d because a b c are energy equation not work

4 0

3 years ago

Which equation is correct according to Ohm’s law?

Korvikt [17]

You didn't give us anything other than the question. No options are provided so I cannot answer. Nobody can.

4 0

3 years ago

Read 2 more answers