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Brut [27]
3 years ago
13

A student does 25 J of work on the handle of a pencil sharpener. If the pencil sharpener does 20 J of work on the pencil, what i

s the efficiency of the sharpener?
Physics
1 answer:
allsm [11]3 years ago
3 0

Answer:

80%

Explanation:

Efficiency of machine = work output/work input  ×100 %

From question, work output = 20J

Work input = 25J.

Therefore efficiency = 20/25 × 100 %

Efficiency = 20×4 %

Efficiency = 80%

I hope this was helpful, please mark as brainliest

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A 2.60 kg lion runs at a speed of 5.00 m/s until he sees his prey. The lion then speeds up 8.00 m/s to catch it. How much work d
ELEN [110]

Answer: 50.7 J

Explanation:

Given

mass of lion is  m=2.6\ kg

The initial speed of the lion is v_1=5\ m/s

increased speed of lion is v_2=8\ m/s

Initially, its kinetic energy is K_1=\frac{1}{2}mv_1^2

Final kinetic energy k_2=\frac{1}{2}mv_2^2

work did by lion after speed up is k_2-k_1

\Rightarrow W=\dfrac{1}{2}\times 2.6[8^2-5^2]\\\\\Rightarrow W=1.3\times [39]=50.7\ J

5 0
2 years ago
9. Seismic waves are
Brilliant_brown [7]

d. both a and b

Explanation:

Seismic waves are both transverse and compressional or longitudinal waves.

A seismic wave is an elastic wave that causes a sudden disturbance in earth materials.

  • Seismic waves are both longitudinal and transverse waves.
  • There are two main types of seismic waves which are the surface and body waves.
  • The surface waves runs on the earth surface. These are the rayleigh and love waves.
  • The surface waves causes damages on the earth surface as they are both longitudinal and transverse.
  • Body waves moves within the earth surface. They are p-waves and s-waves.
  • P-waves are longitudinal or compressional waves that propagates within the earth surface.
  • S-waves are transverse waves that moves perpendicularly to their direction of propagation.

Learn more:

Seismograph brainly.com/question/11292835

#learnwithBrainly

6 0
3 years ago
Ancient Greek philosophers spent lots of time thinking about science and imaging explanations for the natural world. What part o
Illusion [34]

Answer:

Testing

Explanation:

Ancient Greek philosophers lived with the ideology to simply contemplate life. This means that their whole life revolved around thinking and questioning everything. This would include creative thinking, because they would sometimes come up with theories which require creativeness. They would often debate with their friends as to why their theory should be accepted or what their opinions were on the matter. More often than not, they argued a lot, and many philosophers went against some powerful people in the community and some were even sentenced to death.

The main process they didn't/couldn't do was the testing. They could never test certain theories because they did not have the means to.

4 0
2 years ago
Analisis morfologico palabra yo gane el primer premio
ale4655 [162]

Answer:

eres raro jajaja pero eres realmente genial y ordenado espero que esto te ayude jajaja

Explanation:

5 0
3 years ago
What are the defining characteristics of matter
Ymorist [56]
Matter occupies space and has mass
6 0
3 years ago
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