2 years ago

What is true about coal as an energy source

Physics

1 answer:

seropon [69]2 years ago

6 0

Nonrenewable............................

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Ultraviolet light with a frequency of 3.00x10^15 Hz strikes a metal surface and ejects electrons that have a maximum kinetic ene

oksian1 [2.3K]

Answer:

Explanation:

Frequency of 3 x 10¹⁵ , wavelength = 3 x 10⁸/3 x 10¹⁵ = 10⁻⁷ m = 1000A.

Energy in eV = 12375/1000 = 12.375 eV.

Maximum kinetic energy of ejected electrons = 6.1 eV

Work function = 12.375 - 6.1 = 6.275 eV.

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3 years ago

A 60.0 kg ballet dancer stands on her toes during a performance with four square inches (26.0 cm2) in contact with the floor. Wh

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Answer:

Explanation:

Given

Mass of dancer $m=60\ kg$

Area of contact $A=26\ cm^2$

(a)If dancer is stationary

Pressure exerted by Floor is given by load per unit area of contact

$P=\frac{weight}{A}$

$P=\frac{mg}{A}$

$P=\frac{60\times 9.8}{26\times 10^{-4}}$

$P=226.153 kN$

(b)If dancer is leaping upwards with an acceleration of $a=5 m/s^2$

So apparent weight of dancer is $W'=mg+ma$

$W'=m(g+a)=60\cdot (9.8+5)$

$W'=888\ N$

$Pressure=\frac{W'}{A}$

$Pressure=\frac{888}{26\times 10^{-4}}$

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A car’s velocity changes from 35 m/s to stopped in 13 seconds. Calculate<br> acceleration.

padilas [110]

Answer:

Acceleration = 3m/s^2

Vf= 0 Vi =35m/s t= 13s

Explanation:

$Acceleration = \frac{Change in velocity}{Change in time}\\ = \frac{35m/s}{13s}\\ a = 2.69m/s^2\\ a = 2.7m/s^2\\ a = 3m/s^2$

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Explanation:

hindi ko po alam yun e show pic mo

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PLEASE HELP I WILL GIVE BRALINEST

Greeley [361]

Weight: it is the gravitational pull applied on a body by the earth’s surface
Mass: it is the amount of matter present

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