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zmey [24]
2 years ago
15

Which letter explains why no machine is 100 percent efficient.

Physics
1 answer:
kondaur [170]2 years ago
4 0

Answer:

A

Explanation:

Think about rubbing your hands together- the friciton produces heat

You might be interested in
The color of light emitted by a hot, solid object depends on ______.
nadya68 [22]

Answer:

The correct option is (A).

Explanation:

When the temperature of the hot solid object increases then the radiation which emits from it gets shifted to smaller wavelength or higher frequencies. The hot appears red color.

The total energy emitted of a hot solid object is directly proportional to the fourth power of the temperature of the black body.

For example, when we switch on the light bulb, initially the radiation of the bulb appears dimmer. Then, it will become brighter. Then, it will turn yellow and then it becomes even white.

The color of the light emitted by a hot solid object depends on the temperature of the object.

Therefore, the correct option is (A).

4 0
3 years ago
A long, straight wire of radius R carries a steady current I that is uniformly distributed through the cross section of the wire
vitfil [10]

Answer:

a

  When r \ge R

      B =  \frac{ \mu_o *  I}{ 2 \pi r }

b

 When r< R

   B =  [\frac{\mu_o *  I }{ 2 \pi R^2} ]* r

Explanation:

From the question we are told that

   The  radius is  R  

   The  current is  I

    The  distance from the center

Ampere's law is mathematically represented as

       B[2 \pi r]  =  \mu_o  *  \frac{I r^2  }{R^2 }

      B =  \frac{ \mu_o}{2 \pi }  *  \frac{r}{R^2}

When r \ge R

=>     B =  \frac{ \mu_o *  I}{ 2 \pi r }

But when r< R

   B =  [\frac{\mu_o *  I }{ 2 \pi R^2} ]* r

     

4 0
3 years ago
7) The acceleration due to gravity near the surface of Mars is about one-third of the value
Doss [256]

Answer:

C) three times slow than on earth

8 0
3 years ago
How can you find the net force if two forces act in opposite directions?
Tresset [83]

Then the magnitude of the net force is the difference between the two forces,
and its direction is the same as the direction of the greater one.


4 0
3 years ago
A person pushes a refrigerator across a horizontal floor. The mass of the refrigerator is 110 kg, the coefficient of static fric
Law Incorporation [45]

Answer:

Explanation:

mass of refrigerator, m = 110 kg

coefficient of static friction, μs = 0.85

coefficient of kinetic friction, μk = 0.59

(a) the minimum force required to just start the motion in refrigerator

F = μs x mg

F = 0.85 x 110 x 9.8

F = 916.3 N

(b) The force required to move the refrigerator with constant speed

F' = μk x mg

F' = 0.59 x 110 x 9.8

F' = 636.02 N

(c) Let a be the acceleration.

Net force = Applied force - friction force

F net = 950 - 636.02

F net = 313.98 N

a = F net / mass

a = 313.98 / 110

a = 2.85 m/s²

4 0
3 years ago
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