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3 years ago

Is there any machine that is 100% efficient? why?why not

Physics

1 answer:

denis-greek [22]3 years ago

7 0

Answer:

No, it's not there.

Explanation:

For a machine to be 100% efficient, it has to be with an output which is equal to its input. But machines have an out put less than an input, hence efficiency below 100%.

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How to find id in this app.

AysviL [449]

Go and click to the invitation bar and you can find an option written as " search friends " . Then it's easy to find that unknown user if you're pretty fond with his/her username and DP ( display picture ).

6 0

3 years ago

A rock is dropped from a garage roof from rest. the roof is 6.0 m from the ground. determine the velocity of the rock as it hits

Dmitrij [34]

From rest, a rock is dropped from a garage roof. The roof is 6.0 meters above ground level. The rock will reach the earth at a speed of 10.849 meters per second.

<h3>What is velocity?</h3>

The change of displacement with respect to time is defined as the velocity. Velocity is a vector quantity.

it is a time-based component. Velocity at any angle is resolved to get its component of x and y-direction.

Given data:

V(Final velocity)=? (m/sec)

h(height)= 6.0 m

u(Initial velocity)=0 m/sec

g(gravitational acceleration)=9.81 m/s²

Newton's third equation of motion:

$\rm v_y^2 = u_y^2+ 2gh \\\\\rm v_y^2 = 0+ 2gh\\\\\ v_y= \sqrt{2\times 9.81 \ (m/s^2)\times 6.0 (m)} \\\\ v_y=10.849 \ m/sec$

Hence, the velocity of the rock as it hits the ground will be 10.849 m/sec.

To learn more about the velocity refer to the link ;

brainly.com/question/862972

#SPJ1

7 0

2 years ago

A clock moves past you at a speed of 0.9 c. How much time passes for you for each second that elapses on the moving clock?

Zigmanuir [339]

Answer:

Explanation:

Time dilation formula is

T = T₀ / √ 1-v²/c²

T₀ is time elapsed in moving reference , T time elapsed in stationary reference.

Here T₀ = 1 second

T = 1/√ 1-0.9² = 1/.4358 = 2.3 second

So 2.3 second will pass for each second on moving reference.

6 0

3 years ago

Characteristics that a scientific measuring tool should have

bixtya [17]

Answer:

RELIBILITY - is the consistency of your measurement, or the degree to which an

instrument measures the same way each time it is used under the same condition with the

same subjects. In short, it is the repeatability of your measurement. A measure is considered

reliable if a person's score on the same test given twice is similar. It is important to

remember that reliability is not measured, it is estimated. A good instrument will produce

consistent scores. An instrument’s reliability is estimated using a correlation coefficient of

one type or another.

VALIDITY

VALIDITY - Validity is the extent to which a test measures what it claims to measure. It is

vital for a test to be valid in order for the results to be accurately applied and interpreted.

Validity isn’t determined by a single statistic, but by a body of research that demonstrates

the relationship between the test and the behavior it is intended to measure. There are three

types of validity: It is the strength of our conclusions, inferences or propositions. More

formally, Cook and Campbell (1979) define it as the "best available approximation to the

truth or falsity of a given inference, proposition or conclusion."

PRACTICIBILITY

PRACTICIBILITY - It should be feasible & usable. Quality of being usable in context to the

objective to be achieved.

USABILITY

USABILITY(practicality) ease in administration, scoring, interpretation and application, low

cost, proper mechanical make – up

MEASUREABILITY

MEASUREABILITY - It should measure the objective to be achieved.

Explanation:

5 0

2 years ago

To tugboats pull a disabled supertanker. Each tug exerts a constant force of 1.50•10^6 N, one at an angle 19.0° west of north, a

irina1246 [14]

Answer:

Work done by a tug boat, W = 1.735 x 10⁸ J

Explanation:

Given,

The of each tugboat, F = 1.5 x 10⁶ N

The angle of each tugboat forms with the resultant force, θ = 19°

The displacement of the supertanker, s = 710 m

The individual tugboat will be responsible for the displacement, d = 710/2

= 355 m

The displacement component in each tugboat direction = 355 · sin θ meter

Therefore, the work done by each tugboat is

W = F x S joules

Substituting the values in the above equation

W = 1.5 x 10⁶ x 355 · sin θ

= 1.735 x 10⁸ J

Hence, the work done by each tugboat is, W = 1.735 x 10⁸ J

6 0

3 years ago