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2 years ago

explain how the efficiency of an ideal meachine compares with the efficiency of a real machine. For 25 POINTS

2 answers:

7 0

An ideal machine is 100% efficient, meaning it puts out all of the energy you put in (ie. no loss due to friction..) A real machine can never be 100% efficient. You must always put more energy Into a real machine than you get out of it.

Tcecarenko [31]2 years ago

5 0

The efficiency of such a machine is 100%. An ideal machine is one in which no part of the input energy to the machine gets wasted and the whole input energy is converted into the useful work. The efficiency of such a machine is 100%.
PLEASE MARK ME AS BRAINLIEST CAUSE IVE NEVER GOT BRAINLIEST BEFORE AND HAVE A GOOD DAY !

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Bicyclists in the Tour de France do enormous amounts of work during a race. For example, the average power per kilogram generate

tigry1 [53]

Explanation:

It is given that,

Average power per unit mass generated by Lance, $\dfrac{P}{m}=6.5\ W/kg$

$P=6.5\times 75=487.5\ W$

(a) Distance to cover race, $d = 160\ km =160\times 10^3\ m$

Average speed of the person, v = 11 m/s

If t is the time taken to cover the race.

$t=\dfrac{d}{v}$

$t=\dfrac{160\times 10^3\ m}{11\ m/s}$

t = 14545.46 s

Let W is the work done. The relation between the work done and the power is given by :

$P=\dfrac{W}{t}$

$W=P\times t$

$W=487.5\times 14545.46$

W = 7090911.75 J

(b) Since, $1\ J=2.389\times 10^{-4}\ calories$

So, in 7090911.75 J, $W=7090911.75 \times 2.389\times 10^{-4}$

W = 1694.01 J

Hence, this is the required solution.

6 0

3 years ago

A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake.

ArbitrLikvidat [17]

Answer:

L = 499 m

Explanation:

If we assume that the speed of sound is constant, that travels along a straight line, and that the echo is instantaneous, we can find the total distance travelled by the sound, as follows, just applying the definition of average velocity:

$\Delta x = v_{s} * t = 343 m/s* 2.91 s = 998 m$

If we assume that the time needed to reach to the cliff, is the same used for the return travel, the length of the lake will be exactly half of the total distance calculated:

$l_{lake} = \frac{\Delta x}{2} = \frac{998m}{2} = 499 m$

The length of the lake is 499 m.

8 0

3 years ago

How can you prove to be an initiator?

lozanna [386]

An initiator is someone who starts something. Example: She initiated the fight.

6 0

3 years ago

Which renewable resource produces the most electricity in the United States? geothermal energy solar energy wind power hydroelec

Anna71 [15]

Hydroelectricity is the best answer.

This is an article by the EIA, but the pie graph is the most helpful: https://www.eia.gov/energyexplained/?page=us_energy_home

8 0

3 years ago

Read 2 more answers

Describe a situation in which you can accelerate even though your speed doesn’t change.

KATRIN_1 [288]

Acceleration is not the same as speeding up. It refers to any modification of motion's direction or speed. Accelerated motion is any movement that is not constant speed in a straight line.

<h3>What is meant by acceleration?</h3>

The rate at which an object's velocity for time changes is referred to as acceleration in mechanics. They are vector quantities and accelerations. The direction of the net force acting on an object determines the direction of its acceleration.

An object's velocity can alter depending on whether it moves faster or slower or in a different direction. A falling apple, the moon orbiting the earth, and a car stopped at a stop sign are a few instances of acceleration.

The rate at which velocity changes is called acceleration. Acceleration typically indicates a change in speed, but not necessarily. An item that follows a circular course while maintaining a constant speed is still moving forward because the direction of its motion is shifting.

To learn more about acceleration refer to:

brainly.com/question/605631

#SPJ4

6 0

2 years ago