All categories

3 years ago

The value of efficiency is never 100% or more in practice. why

1 answer:

3 0

Answer: Because of presence of friction in most cases as friction exists in ever machine/body, so whenever it works, friction causes heat and sound energy as well, hence, proving that a system cannot be 100% efficient due to friction.

You might be interested in

We wrap a light, nonstretching cable around a 10.0 kg kg solid cylinder with diameter of 38.0 cm cm . The cylinder rotates with

amm1812

Answer: 14.16

Explanation:

Given

d = 38cm

r = d/2 = 38/2 = 19cm = 0.19m

K.E = 510J

m = 10kg

I = 1/2mr²

I = 1/2*10*0.19²

I = 0.18kgm²

When it has 510J of Kinetic Energy then,

510J = 1/2Iω²

ω² = 1020/I

ω² = 1020/0.18

ω² = 5666.67

ω = √5666.67 = 75.28 rad/s

Velocity is the block, v = ωr

V = 75.28 * 0.19

V = 14.30m/s

The "effective mass" M of the system is

M = (14.0 + ½*10.0) kg = 19.0 kg

The motive force would be

F = ma

F = 14 * 9.8

F = 137.2N

so that the acceleration would be

a = F/m

a = 137.2/19

a = 7.22m/s²

Finally, using equation of motion.

V² = u² + 2as

14.3² = 0 + 2*7.22*s

204.49 = 14.44s

s = 204.49/14.44

s = 14.16m

6 0

3 years ago

the average power of the Sun is 3.79x1026 Watts, answer the following questions: 13. What is the average intensity of light at E

Lemur [1.5K]

Explanation:

Given that,

Average power of sun $P=3.79\times10^{26}\ Watt$

We need to calculate the intensity of light at Earth's position

Using formula of intensity

$I=\dfrac{P_{avg}}{4\pi r^2}$

Where, I = intensity

P = power

Put the value into the formula

$I=\dfrac{3.79\times10^{26}}{4\pi\times(1.496\times10^{11})^2}$

$I=1347.616\ W/m^2$

So, The intensity is 1347.616 W/m².

(A). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective

Using formula for fully reflective

$P = \dfrac{2I}{c}$

Put the value into the formula

$P=\dfrac{2\times1347.616}{3\times10^{8}}$

$P=8.984\times10^{-6}\ N/m$

(B). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective

Using formula for fully absorptive

$P=\dfrac{I}{c}$

$P=\dfrac{1347.616}{3\times10^{8}}$

$P=4.492\times10^{-6}\ N/m$

Hence, This is the required solution.

6 0

3 years ago

There are Z protons in the nucleus of an atom, where Z is the atomic number of the element. An α particle carries a charge of +2

qaws [65]

Answer:

$r = 2.84 \times 10^{-14} m$

Explanation:

As per energy conservation we know that the electrostatic potential energy of the charge system is equal to the initial kinetic energy of the alpha particle

So here we can write it as

$\frac{1}{2}mv^2 = \frac{k(2e)(ze)}{r}$