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IceJOKER [234]
3 years ago
11

A cargo elevator on Earth (where g = 10 m/s2) lifts 3000 kg upwards by 20 m. 720 kJ of electrical energy is used up in the proce

ss. What is the efficiency of this process?
Physics
1 answer:
MakcuM [25]3 years ago
8 0

Answer: 83%

Explanation:

Efficiency of the process = work output/work input × 100%

Work input is the energy used up in the process = 720,000Joules

Work output = Force × distance

= (3000×10)× 20

= 600000 Joules

Efficiency= 600000/720000 × 100

= 0.83×100

= 83%

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A 4,000-kg car traveling at 20m/s hits a wall with a force of 80,000 N and comes to a stop. What was the impact time?
Nookie1986 [14]
Rate of change of momentum = impact force
(m*v-m*u)/t = F
4000*20/t = 80000 (note: v is zero as it stopped)
<span>soo, t = 1 sec</span>
7 0
3 years ago
How does gravity relate to potential energy?
Nookie1986 [14]

Answer:

the potential energy a massive object has in relation to another massive object due to gravity

3 0
2 years ago
Read 2 more answers
During the spin cycle of a washing machine, the clothes stick to the outer wall of the barrel as it spins at a rate as high as 1
Darya [45]

To answer the two questions, we need to know two important equations involving centripetal movement:

v = ωr (ω represents angular velocity <u>in radians</u>)

a = \frac{v^{2}}{r}

Let's apply the first equation to question a:

v = ωr

v = ((1800*2π) / 60) * 0.26

Wait. 2π? 0.26? 60? Let's break down why these numbers are written differently. In order to use the equation v = ωr, it is important that the units of ω is in radians. Since one revolution is equivalent to 2π radians, we can easily do the conversion from revolutions to radians by multiplying it by 2π. As for 0.26, note that the question asks for the units to be m/s. Since we need meters, we simply convert 26 cm, our radius, into meters. The revolutions is also given in revs/min, and we need to convert it into revs/sec so that we can get our final units correct. As a result, we divide the rate by 60 to convert minutes into seconds.

Back to the equation:

v = ((1800*2π)/60) * 0.26

v = (1800*2(3.14)/60) * 0.26

v = (11304/60) * 0.26

v = 188.4 * 0.26

v = 48.984

v = 49 (m/s)

Now that we know the linear velocity, we can find the centripetal acceleration:

a = \frac{v^{2}}{r}

a = \frac{49^{2}}{0.26}

a = 9234.6 (m/s^{2})

Wow! That's fast!

<u>We now have our answers for a and b:</u>

a. 49 (m/s)

b. 9.2 * 10^{3} (m/s^{2})

If you have any questions on how I got to these answers, just ask!

- breezyツ

5 0
2 years ago
Which person will most likely hear the loudest sound?
Nataliya [291]

Person standing on A will hear the loudest sound

Explanation:

The intensity of a sound wave (which is proportional to the loudness of the sound) follows an inverse square law, which is:

I\propto \frac{1}{r^2}

where

I is the intensity of the wave

r is the distance from the source of the sound

This equation means that the intensity of the sound wave (and therefore, its loudness) is inversely proportional to the square of the distance  from the source: therefore,

  • As we get closer to the source of sound, the loudness increases
  • As we move away from the source of sound, the loudness decreases

Therefore, the person that will hear the loudest sound is the one standing closer to the source, and therefore person A.

Learn more about sound waves:

brainly.com/question/4899681

#LearnwithBrainly

6 0
3 years ago
Read 2 more answers
Carlos gives a grocery cart a 60-N push. The cart has a mass of 40 kg. What is the cart's acceleration?
andre [41]
<h3>Answer:</h3>

1.5 m/s²

<h3>Explanation:</h3>

We are given;

Force as 60 N

Mass of the Cart as 40 kg

We are required to calculate the acceleration of the cart.

  • From the newton's second law of motion, the rate of change in momentum is directly proportional to the resultant force.
  • That is, F = ma , where m is the mass and a is the acceleration

Rearranging the formula we can calculate acceleration, a

a = F ÷ m

  = 60 N ÷ 40 kg

  = 1.5 m/s²

Therefore, the acceleration of the cart is 1.5 m/s²

3 0
3 years ago
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