3 years ago

A child is sliding down a slide at the playgound. is mechanicalenergy conserved

1 answer:

5 0

No. Mechanical energy is not conserved. There's quite a bit of friction on the slide. So some of the potential energy is lost to heat on the way down, and the child arrives at the bottom with hot pants and less kinetic energy than you might expect.

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The copper wire and bulb is connected in a series with 220 V electric supply. Why only an electric bulb glows where as the coppe

Sveta_85 [38]

-- In a series circuit, the current ( I ) is the same at every point.

-- The power dissipated by any section of the circuit is I² x Resistance.

-- The wire has very low resistance, so I²R is very low dissipated power.

-- The filament in the bulb has most all of the resistance in the circuit,
so it dissipates virtually all the power of the circuit, and certainly much
more than the wires do.

7 0

3 years ago

Please need help with this

nikdorinn [45]

It's going to be the third one because conductors allow energy to flow but insulators don't.

8 0

3 years ago

A uniform cylindrical grindstone has a mass of 15.0 kg and a radius of 18.6 cm. The grindstone reaches a rotational velocity of

tekilochka [14]

Answer:

$n \approx 5.778\times 10^{-4}\,rev$

Explanation:

The Work-Energy Theorem is applied herein:

$-\frac{1}{4}\cdot m_{cyl}\cdot R^{2}\cdot \omega^{2} = - \mu_{k}\cdot N\cdot r \cdot 2\pi \cdot n$

The number of turns needed to stop the grindstone is:

$n = \frac{m_{cyl}\cdot R^{2}\cdot \omega^{2}}{4\cdot \mu_{k}\cdot N \cdot r\cdot 2\pi}$

$n = \frac{(15\,kg)\cdot (0.186\,m)^{2}\cdot [(1.83\,\frac{rev}{min} )\cdot (\frac{2\pi\,rad}{1\,rev} )\cdot (\frac{1\,min}{60\,s} )]^{2}}{4\cdot (0.80)\cdot (8.82\,N)\cdot(0.186\,m)\cdot 2\pi}$