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3 years ago

Someone help me with this ASAP!!

Physics

2 answers:

olya-2409 [2.1K]3 years ago

7 0

D. Water vapor in the air cools and forms clouds

Lelechka [254]3 years ago

4 0

Answer: the last choice.

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It has been suggested that a heat engine could be developed that made use of the fact that the temperature several hundred meter

lesantik [10]

Answer:

efficiency = 5.4%

Explanation:

Efficiency of heat engine is given as

$\eta = \frac{W}{Q_{in}}$

now we will have

$W = Q_1 - Q_2$

so we will have

$\eta = 1 - \frac{Q_2}{Q_1}$

now we know that

$\frac{Q_2}{Q_1} = \frac{T_2}{T_1}$

so we have

$\eta = 1 - \frac{T_2}{T_1}$

$\eta = 1 - \frac{273+6}{273+22}$

$\eta = 0.054$

so efficiency is 5.4%

8 0

3 years ago

What comes before Action-reaction?

Anarel [89]

These two forces are called action and reaction forces and are the subject of Newton's third law of motion. Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects.

4 0

3 years ago

An automobile travels on a straight road for 40 km at 30 km/h. It then continues in the same direction for another 40 km at 60 k

Butoxors [25]

Answer:

The average velocity is 40km/h.

Explanation:

The average velocity is $\bar{v}=\frac{\Delta x }{\Delta t}$ , where $\Delta x$ is the distance traveled and $\Delta t$ the time elapsed.

The distance traveled is clearly 80km since it's all done in the same direction, we only need to know the time elapsed. For this we calculate the time elapsed on the first part, and add it to the time elapsed on the second part using always the formula $\Delta t=\frac{\Delta x }{v}$ , where v is the velocity on each part, which is constant.

The time elapsed for the first part is $\Delta t_1=\frac{40 km}{30km/h}=\frac{4}{3}h$ , and the time elapsed for the second part is $\Delta t_2=\frac{40 km}{60km/h}=\frac{2}{3}h$ , giving us a total time of $\Delta t_1+\Delta t_2=\frac{4}{3}h+\frac{2}{3}h$ =2h.

Finally, we can calculate the average velocity: $\bar{v}=\frac{80km}{2h}=40km/h$ .

6 0

3 years ago

Given that o.2i+bj+o.4k is a unit vector,what is the value of b?

pishuonlain [190]

Answer:

b = 0.89

Explanation:

The given vector is, $A=0.2i+bj+0.4k$

A is a unit vector

We need to find the value of b.

For a unit vector, |A| = 1

So,

$0.2^2+b^2+0.4^2=1\\\\0.04+b^2+0.16=1\\\\0.2+b^2=1\\\\b^2=1-0.2\\\\b=0.89$

So, th value of b is 0.89.

6 0

3 years ago

You need to repair a broken fence in your yard. The hole in your fence is

Nadusha1986 [10]

Answer:

cost = $ 243.00

Explanation:

This exercise must assume that it uses a complete table for each piece, we can use a direct ratio of proportions, if 1 table is 0.20 m wide, how many tables will be 3.00 m

#_tables = 3 m (1 / 0.20 m)

#_tables = 15 tables

Let's use another direct ratio, or rule of three, for cost. If a board costs $ 16.20, how much do 15 boards cost?

Cost = 15 (16.20 / 1)

cost = $ 243.00

3 0

3 years ago