All categories

3 years ago

If the _____ work on a simple machine equals the output work, the machine is said to be 100% efficient.

Physics

1 answer:

omeli [17]3 years ago

3 0

<h3>Answer:</h3>

Input work

<h3>Explanation:</h3>

Concept being tested: Efficiency of machines

Therefore we need to know what is the efficiency of a machine

Efficiency of a machine is the ratio of work output of machine to the work input expressed as a percentage.

Thus;

Efficiency = (Work output ÷ Work input) × 100%

Therefore, if the work input is equal to the work output then the efficiency of the machine will be 100%.

Most machines are not 100% efficient due to loss of energy in form of heat due to friction of the moving parts of the machine.

You might be interested in

A rope is tied to a box and used to pull the box 2.3 m along a horizontal floor. The rope makes an angle of 30∘ with the horizon

Savatey [412]

Answer:

Answered

Explanation:

A) The work done by gravity is zero because displacement and the gravitational force are perpendicular to each other.

W= FS cosθ

θ= 90 ⇒cos90 = 0 ⇒W= 0

B) work done by tension

W= Tcosθ×S= 5cos30×2.30= 10J

C) Work done by friction force

W= f×s=1×2.30= 2.30 J

D) Work done by normal force is Zero because the displacement and the normal force are perpendicular to each other.

E) The net work done= Work done by tension in the rope - frictional work

=10-2.30= 7.7 J

6 0

3 years ago

A car passes point “A” and then 120 meters later. It’s velocity was measured 21 m/s. If it’s acceleration was constant at 0.853

Norma-Jean [14]

Recall that

${v_f}^2-{v_i}^2=2a\Delta x$

where $v_i$ and $v_f$ are the initial and final velocities, respecitvely; $a$ is the acceleration; and $\Delta x$ is the change in position.

So we have

$\left(21\dfrac{\rm m}{\rm s}\right)^2-{v_i}^2=2\left(0.853\dfrac{\rm m}{\mathrm s^2}\right)(120\,\mathrm m)$

$\implies v_i\approx\boxed{15.4\dfrac{\rm m}{\rm s}}$

(Normally, this equation has two solutions, but we omit the negative one because the car is moving in one direction.)

7 0

3 years ago

The results of a recent television survey of American TV households revealed that 86 out of every 100 TV households have at leas

Lelechka [254]

Answer:

$q = \dfrac{14}{100}$

Explanation:

given,

86 out of every 100 TV households have at least one remote control

Probability of any material is calculated by.

$Probability = \dfrac{favourable\ outcome}{Total\ outcome}$

$P(at\ least\ one\ remote\ control)=\dfrac{86}{100}$

$P(at\ least\ one\ remote\ control)=0.86$

now, Calculating probability that at least one remote control

q = 1 - 0.86

q = 0.14

$P(doesnot\ have\ at\ least\ one\ remote\ control)=\dfrac{14}{100}$

$q = \dfrac{14}{100}$

7 0

3 years ago

Many industries are powered via distant power stations. Calculate the current flowing through a 7,300m long 10. copper power lin

Oliga [24]

Answer:

Current, I = 1000 A

Explanation:

It is given that,

Length of the copper wire, l = 7300 m

Resistance of copper line, R = 10 ohms

Magnetic field, B = 0.1 T

$\mu_o=4\pi \times 10^{-7}\ T-m/A$

Resistivity, $\rho=1.72\times 10^{-8}\ \Omega-m$

We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :

$R=\rho \dfrac{l}{A}$

$R=\rho \dfrac{l}{\pi r^2}$

$r=\sqrt{\dfrac{\rho l}{R\pi}}$

$r=\sqrt{\dfrac{1.72\times 10^{-8}\times 7300}{10\pi}}$

r = 0.00199 m

$r=1.99\times 10^{-3}\ m=2\times 10^{-3}\ m$

The magnetic field on a current carrying wire is given by :

$B=\dfrac{\mu_o I}{2\pi r}$

$I=\dfrac{2\pi rB}{\mu_o}$

$I=\dfrac{2\pi \times 0.1\times 2\times 10^{-3}}{4\pi \times 10^{-7}}$

I = 1000 A

So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.

4 0

3 years ago

What do fuel cells, batteries and, solar cells have in common A.the all produce static electricity B. they are all sources of di

Vaselesa [24]

The correct answer is B :)

3 0

4 years ago

Read 2 more answers