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Grace [21]
3 years ago
11

An engine absorbs 2150 J as heat from a hot reservoir and gives off 750 J as heat to a cold reservoir during each cycle. What is

the efficiency of the engine?
Physics
1 answer:
tia_tia [17]3 years ago
6 0

Answer:

65.2 %

Explanation:

Let Q1 = Heat absorbed by the system

Q2 = Heat released by the system

e= (1 - (Q2/Q1)) x 100

e= (1 - (750/2150)) x 100

e= (1 - 0.348) x 100

e= 0.652 x 100

e= 65.2 %

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Which characteristic does inertia describe
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Answer:

Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed, or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight line at a constant speed, when no forces act upon them.

Explanation:

mark me brainlist if i help

3 0
3 years ago
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An object blocks the path of a wave causing the wave to change direction is called what
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"Reflection" is the change direction of waves when blocked by obstacle

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If temp. gets cold resistance in thermostat increases so voltage across it increases AND LED lights brighter. I understand every
Valentin [98]

Normally, when something gets colder, its electrical resistance gets smaller.  This is true of component-A in the drawing ... a simple resistor.

The component labeled 'B' has a strange and unusual symbol, and it's not a simple resistor.  It's a "thermistor".  The word "thermal" always has something to do with heat, and "thermistor" comes from "thermal resistor.  These things can be manufactured either way ... using different materials, a thermistor can be manufactured so that its resistance goes UP, or goes DOWN, or doesn'tchange when it gets colder.  I'm pretty sure that's what's going on here.

When this circuit gets colder, resistance-A gets smaller, but resistance-B either gets bigger OR doesn't change.  Either way, the voltage across B increases.  Since the LED is connected directly across B, the current through it depends on that voltage, so the LED gets more current, and becomes brighter, when A and B both get colder.

This circuit could actually be a very useful device.  If you took out the LED and put a voltmeter in its place, then the reading on the voltmeter would tell you the temperature of wherever you put the two components A and B.

5 0
3 years ago
Suppose two children push horizontally, but in exactly opposite directions, on a third child in a wagon. The first child exerts
Nata [24]

(a) The system of interest if the acceleration of the child in the wagon is to be calculated are the wagon and the children outside the wagon.

(b) The acceleration of the child-wagon system is 0.33 m/s².

(c) Acceleration of the child-wagon system is zero when the frictional force is 21 N.

<h3>Net force on the third child</h3>

Apply Newton's second law of motion;

∑F = ma

where;

  • ∑F is net force
  • m is mass of the third child
  • a is acceleration of the third child

∑F = 96 N - 75 N - 12 N = 9 N

Thus, the system of interest if the acceleration of the child in the wagon is to be calculated are;

  • the wagon
  • the children outside the wagon

<h3>Free body diagram</h3>

           →                 →              Ф                         ←

         1st child      friction       wagon                2nd child

<h3>Acceleration of the  child and wagon system</h3>

a = ∑F/m

a = 9 N / 27 kg

a = 0.33 m/s²

<h3>When the frictional force is 21 N</h3>

∑F = 96 N - 75 N - 21 N = 0 N

a = ∑F/m

a = 0/27 kg

a = 0 m/s²

Learn more about net force here: brainly.com/question/14361879

#SPJ1

7 0
2 years ago
What is the next step if the data from an investigation do not support the original hypothesis? A. The data are revised to suppo
Leno4ka [110]
I believe the answer is D. <span>The hypothesis is revised and another experiment is conducted.</span>
5 0
3 years ago
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