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Marina86 [1]
3 years ago
14

A person is pushing a box. The net external force on the 60-kg box is stated to be 90 N. If the force of friction opposing the m

otion is 30 N, what is the acceleration of the box?a. 0.66 m/s2b. 1.5 m/s2c. 2.0 m/s2
Physics
1 answer:
Tems11 [23]3 years ago
5 0

Answer:

b.1.5m/s^2

Explanation:

We are given that

Mass of box=60kg

Net external force applied on the box=90 N

Friction force =30N

We have to find the acceleration of the box.

We know that

Net external force=ma

Substitute the values then we get

90=60a

a=\frac{90}{60}=1.5m/s^2

Hence, option b is true.

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Answer:

because some waste heat is always produced produced in a heat engine.

Explanation:

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Suppose you have two solid bars, both with square cross-sections of 1 cm2. They are both 24.6 cm long, but one is made of copper
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Explanation:

Expression to calculate thermal resistance for iron (R_{I}) is as follows.

             R_{I} = \frac{L_{I}}{k_{I} \times A_{I}}  

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Thermal resistance for copper (R_{c}) = \frac{L_{c}}{k_{c} \times A_{c}}[/tex]

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Now, expression for the transfer of heat per unit cell is as follows.

           Q = \frac{(100^{o} - 0^{o}}{\frac{L_{I}}{k_{I}.A_{I}} + \frac{L_{c}}{k_{c}.A_{c}}}

 Putting the given values into the above formula as follows.

       Q = \frac{(100^{o} - 0^{o})}{\frac{L_{I}}{k_{I}.A_{I}} + \frac{L_{c}}{k_{c}.A_{c}}}

  = \frac{(100^{o} - 0^{o})}{21 \times 10^{-2} m[\frac{1}{73 \times 10^{-4}m^{2}} + \frac{1}{386 \times 10^{-4}m^{2}}}

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It is known that heat transfer per unit time is equal to the power conducted through the rod. Hence,

                 P = \frac{Q}{T}

Here, T is 1 second so, power conducted is equal to heat transferred.

So,           P = 2.92 watt

Thus, we can conclude that 2.92 watt power will be conducted through the rod when it reaches steady state.

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When preparing to strip insulation in order to splice conductors, a person should strip the insulation back far enough so that t
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Answer:

Closely fits into the connector.

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Many years ago, scientists believed that an atom was the smallest unit of matter. Eventually, evidence was discovered that indic
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I see the light moving exactly at speed equal to c.

In fact, the second postulate of special relativity states that:
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The problem says that I am moving at speed 2/3 c, so my motion is a uniform motion (constant speed). This means I am in an inertial frame of reference, so the speed of light in this frame must be equal to c.
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