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Zina [86]
3 years ago
11

I’ll give brainliest answer to correct one, please help

Physics
1 answer:
dexar [7]3 years ago
5 0

Answer:

i believe its D because he is not sliding and he is applying force on the wall

Explanation:

hope this helps plz mark brainliest

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In a series circuit of two resistors, the resistors have the same __________; in a parallel circuit of two resistors, the resist
bekas [8.4K]

Answer:

current, voltage

Explanation:

Resistors can both be connected in series and parallel configuration. when a resistor is connected serially, the same amount of current flows through each resistor element but the voltage across each resistor is determined by the magnitude of the resistance of each resistor. However, in a parallel connection, the same voltage is applied across each resistor but different current.

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4 years ago
In a lecture demonstration, a 3.0-m-long vertical string with ten bolts tied to it at equal intervals is dropped from the ceilin
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<span>First of all, the bolts wont hit the ground at equal time intervals because each bolt is constantly increasing. Therefore, the top will have different velocity with the bottom bolt at all times. this means that the bolts will speed up more as they are higher which will make the interval time shorter. therefore, the time will decrease</span>
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4 years ago
Effciency of a lever is never 100% or more. why?Give reason​
Troyanec [42]

Answer:

Ideally, the work output of a lever should match the work input. However, because of resistance, the output power is nearly always be less than the input power. As a result, the efficiency would go below 100\%.  

Explanation:

In an ideal lever, the size of the input and output are inversely proportional to the distances between these two forces and the fulcrum. Let D_\text{in} and D_\text{out} denote these two distances, and let F_\text{in} and F_\text{out} denote the input and the output forces. If the lever is indeed idea, then:

F_\text{in} \cdot D_\text{in} = F_\text{out} \cdot D_\text{out}.

Rearrange to obtain:

\displaystyle F_\text{in} = F_\text{out} \cdot \frac{D_\text{out}}{D_\text{in}}

Class two levers are levers where the perpendicular distance between the fulcrum and the input is greater than that between the fulcrum and the output. For this ideal lever, that means D_\text{in} > D_\text{out}, such that F_\text{in} < F_\text{out}.

Despite F_\text{in} < F_\text{out}, the amount of work required will stay the same. Let s_\text{out} denote the required linear displacement for the output force. At a distance of D_\text{out} from the fulcrum, the angular displacement of the output force would be \displaystyle \frac{s_\text{out}}{D_\text{out}}. Let s_\text{in} denote the corresponding linear displacement required for the input force. Similarly, the angular displacement of the input force would be \displaystyle \frac{s_\text{in}}{D_\text{in}}. Because both the input and the output are on the same lever, their angular displacement should be the same:

\displaystyle \frac{s_\text{in}}{D_\text{in}} =\frac{s_\text{out}}{D_\text{out}}.

Rearrange to obtain:

\displaystyle s_\text{in}=s_\text{out} \cdot \frac{D_\text{in}}{D_\text{out}}.

While increasing D_\text{in} reduce the size of the input force F_\text{in}, doing so would also increase the linear distance of the input force s_\text{in}. In other words, F_\text{in} will have to move across a longer linear distance in order to move F_\text{out} by the same s_\text{out}.

The amount of work required depends on both the size of the force and the distance traveled. Let W_\text{in} and W_\text{out} denote the input and output work. For this ideal lever:

\begin{aligned}W_\text{in} &= F_\text{in} \cdot s_\text{in} \\ &= \left(F_\text{out} \cdot \frac{D_\text{out}}{D_\text{in}}\right) \cdot \left(s_\text{out} \cdot \frac{D_\text{in}}{D_\text{out}}\right) \\ &= F_\text{out} \cdot s_\text{out} = W_\text{out}\end{aligned}.

In other words, the work input of the ideal lever is equal to the work output.

The efficiency of a machine can be measured as the percentage of work input that is converted to useful output. For this ideal lever, that ratio would be 100\%- not anything higher than that.

On the other hand, non-ideal levers take in more work than they give out. The reason is that because of resistance, F_\text{in} would be larger than ideal:

\displaystyle F_\text{in} = F_\text{out} \cdot \frac{D_\text{out}}{D_\text{in}} + F(\text{resistance}).

As a result, in real (i.e., non-ideal) levers, the work input will exceed the useful work output. The efficiency will go below 100\%,

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The gas in a cylinder has a volume of 8 liters at a pressure of 109 kPa. The pressure of the gas is increased to 211 kPa. Assumi
user100 [1]
<span>3.9 L  I believe

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Hunter-Best [27]

Answer:

  • Metals are good conductors of electricity <u>because they have free electrons</u> which help in the transfer of charge from one point to another.

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