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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 thin soap bubble of index of refraction 1.33 is viewed with light of wavelength 550.0nm and appears very bright. Predict a pos
faust18 [17]

Answer:

The possible thickness of the soap bubble = 1.034\times 10^{-7}\ m.

Explanation:

<u>Given:</u>

  • Refractive index of the soap bubble, \mu=1.33.
  • Wavelength of the light taken, \lambda = 550.0\ nm = 550.0\times 10^{-9}\ m.

Let the thickness of the soap bubble be t.

It is given that the soap bubble appears very bright, it means, there is a constructive interference takes place.

For the constructive interference of light through a thin film ( soap bubble), the condition of constructive interference is given as:

2\mu t=\left ( m+\dfrac 12 \right )\lambda.

where m is the order of constructive interference.

Since the soap bubble is appearing very bright, the order should be 0, as 0^{th} order interference has maximum intensity.

Thus,

2\mu t=\left (0+\dfrac 12\right )\lambda\\t=\dfrac{\lambda}{4\mu}\\\ \ = \dfrac{550\times 10^{-9}}{4\times 1.33}\\\ \ = 1.034\times 10^{-7}\ m.

It is the possible thickness of the soap bubble.

6 0
3 years ago
What are some examples of pendulums?
Hatshy [7]
Like a grandfather clock,

A pendulum = a string with a weight(can be anything from a coin to a ring to a ball) is on the end, the pendulum swings back and forth losing a little bit of energy every swing until it comes to a complete stop
8 0
3 years ago
What is current of 12 ohm? help me pleasee​
worty [1.4K]
1 Ampere

Explanation:

1/R = 1/8 + 1/10 + 1/12
1/R = (30 + 24 + 20) / 240
1/R = 74 / 240
R = 240 / 37
R = 120/37 Ohms
We know that,
V = IR
I = V/R
I = 12 / (120/37)
I = 12 × 37/120
I = 37/10
I = 3.7 A
Now,
The current in 12 ohm resistor →
= 1 A
∴ The current in 12 ohm resistor is​ 1 ampere
3 0
2 years ago
How long does it take to do 300 Joules of work with 10 watts of power? 30 sec 20 sec .03 sec .30 sec​
Oksana_A [137]

Answer:

Explanation:

Power=work /time

10watts=300J/time

Time =30 sec

4 0
3 years ago
A frame hanging on a wall is held by two cables. The tension in each cable is 30 N, and the cables make an angle of 45° with the
Dimas [21]

Answer: option D) 42.4 N

The weight of the frame is balanced by the vertical component of tension.

W = T sin θ + T sin θ = 2 T sin θ

The tension in each cable is T = 30 N

Angle made by the cables with the horizontal, θ = 45°

⇒ W = 2×30 N × sin 45° = 2 × 30 N × 0.707 = 42.4 N

Hence, the weight of the frame is 42.4 N. Correct option is D.


6 0
4 years ago
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