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Svetradugi [14.3K]
3 years ago
7

A TV has a power of 130 watts and an efficiency of 80 percent. How much

Physics
1 answer:
elena55 [62]3 years ago
3 0

Answer:

I think A. 104.0 W is wasted add heat.

Explanation:

130 W x 80% = 130 W x 0.8

= 104.0 W

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2. A student places an object with a mass of m on a disk at a position r from the center of the disk. The student starts rotatin
ycow [4]

Answer:

\frac{0.065}{r}

Explanation:

The maximum velocity of an object moving in a curve beyond which it will slide off the curve is given by the relationship in equation (1);

v=\sqrt{\mu gr}....................(1)

where \mu is the coefficient of friction between the object and the surface of the curve, g is acceleration due to gravity and r is the radius of the curve.

Given;

v = 0.8m/s

g = 9.81m/s^2

r = ?

\mu=?

In order to solve for \mu, we can simply make it the subject of formula from equation (1) as follows;

v^2=\mu gr\\hence\\\mu=\frac{v^2}{gr}.................(2)

since we were not given the value of r, we can just substitute other known values, then solve and leave the answer in terms of r.

Therefore;

\mu=\frac{0.8^2}{9.81r}

\mu=\frac{0.64}{9.81r}\\\\\mu=\frac{0.065}{r}

8 0
3 years ago
The amount of energy transported by a wave is most closely related to the wavelength of the wave. True or False?
Artemon [7]
I think its false............ Im pretty sure
3 0
3 years ago
Read 2 more answers
The gravitational force experienced by Earth due to the Moon is ________ the gravitational force experienced by the Moon due to
Vsevolod [243]

The gravitational force experienced by Earth due to the Moon is <u>equal to </u>the gravitational force experienced by the Moon due to Earth.

<u>Explanation</u>:

The force that attracts any two objects/bodies with mass towards each other is defined as gravitational force. Generally the gravitational force is attractive, as it always pulls the masses together and never pushes them apart.

The gravitational force can be calculated effectively using the following formula: F=GMmr^2  

where “G” is the gravitational constant.

Though gravity has the ability to pull the masses together, it is the weakest force in the nature.

The mass of the Earth and moon varies, but still the gravitational force felt by the Earth and Moon are alike.

5 0
3 years ago
You toss a 0.40-kg ball at 9.0 ms/ to a 14-kg dog standing on an iced-over pond. The dog catches the ball and begins to slide on
just olya [345]

Answer:

a)   v_{f} = 0.25 m / s  b) u = 0.25 m / s

Explanation:

a) To solve this problem let's start with the conservation of the moment, for this we define a system formed by the ball plus the dog, in this case all the forces are internal and the moment is conserved

We will write the data

     m₁ = 0.40 kg

     v₁₀ = 9.0 m / s

     m₂ = 14 kg

     v₂₀ = 0

Initial

     po = m₁ v₁₀

Final

     p_{f} = (m₁ + m₂) vf

     po = pf

     m₁ v₁₀ = (m₁ + m₂) v_{f}

      v_{f} = v₁₀ m₁ / (m₁ + m₂)

      v_{f} = 9.0 (0.40 / (0.40 +14)

      v_{f} = 0.25 m / s

b) This is the reference frame of the center of mass of the system in this case the speed of this frame is the speed of the center of mass

      u = 0.25 m / s

In the direction of movement of the ball

c) Let's calculate the kinetic energy in both moments

Initial

     K₀ = ½ m₁ v₁₀² +0

     K₀ = ½ 0.40 9 2

     K₀ = 16.2 J

Final

     K_{f}= ½ (m₁ + m₂) v_{f}2

      K_{f} = ½ (0.4 +14) 0.25 2

    K_{f} = 0.45 J

   

    ΔK = K₀ -  K_{f}

    ΔK = 16.2-0.445

    ΔK = 1575 J

These will transform internal system energy

d) In order to find the kinetic energy, we must first find the velocities of the individual in this reference system.

      v₁₀’= v₁₀ -u

      v₁₀’= 9 -.025

      v₁₀‘= 8.75 m / s

      v₂₀ ‘= v₂₀ -u

      v₂₀‘= - 0.25 m / s

      v_{f} ‘=   v_{f} - u

      v_{f} = 0

Initial

    K₀ = ½ m₁ v₁₀‘² + ½ m₂ v₂₀‘²

    Ko = ½ 0.4 8.75² + ½ 14.0 0.25²

    Ko = 15.31 + 0.4375

    K o = 15.75 J

Final

   k_{f} = ½ (m₁ + m₂) vf’²

  k_{f} = 0

All initial kinetic energy is transformed into internal energy in this reference system

3 0
3 years ago
Two streams merge to form a river. One stream has a width of 8.9 m, depth of 3.8 m, and current speed of 2.3 m/s. The other stre
SpyIntel [72]
<h2>Depth of river is 4.48 m</h2>

Explanation:

Discharge = Area x Velocity

Discharge of river = Discharge of stream 1 + Discharge of stream 2

A_rv_r=A_1v_1+A_2v_2

Area of stream 1 = w₁ x d₁ = 8.9 x 3.8 = 33.82 m²

Area of stream 2 = w₂ x d₂ = 6.5 x 3.9 = 25.35 m²

Velocity of stream 1 = 2.3 m/s

Velocity of stream 2 = 2.6 m/s

Velocity of river = 3 m/s

\texttt{Area of river = }w_r\times d_r=10.7\times d_r

Substituting

             A_rv_r=A_1v_1+A_2v_2\\\\10.7\times d_r\times 3=33.82\times 2.3+25.35\times 2.6\\\\d_r=4.48m

Depth of river = 4.48 m

7 0
3 years ago
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