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Dafna1 [17]
3 years ago
8

Two movers use a rope system to lift a box to a third-story apartment. they do 1,200 j of work on the rope system, and the rope

system does 1,020 j of work on the box. what is the efficiency of the rope system?
Physics
2 answers:
shepuryov [24]3 years ago
8 0
Efficiency = energy output / energy input
Sladkaya [172]3 years ago
8 0

Efficiency = (1020 J / 1200 J) = 85%

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HELPPP<br> why is the united states considered energy rich, while japan is considered energy poor
Temka [501]

Answer:

Energy resources can be measured.  They will include the fossil fuels, geothermal and hydroelectric potential, and increasingly the renewable resources.  When the US list is compared to the World it is considered energy Rich.  When Japan's list is compared to the world standard it considered energy poor.  

A changing technology like nuclear fusion could substantially change the assessment.

Japan does not have any substantial, oil, coal, gas, deposits, while the US does.

Explanation:

6 0
2 years ago
Which of the following diagrams involves a virtual image ?
sergiy2304 [10]

Answer:

The third diagram

Explanation:

  • <u>A virtual image</u> is an image that can not be formed on a screen.
  • <u>A convex lens</u> can form both virtual and real image depending on the position of the object from the lens.
  • A virtual image in convex lens is formed when the object is placed between the focus and the optical center of the lens.
  • In the third diagram, a virtual image is formed because the position of the object is between the focus and the optical center of the convex lens.
7 0
2 years ago
What is the magnitude of the force a 1.5 x 10-3 C charge exerts on a 3.2 x 10-4 C charge located 1.5 m away?
sweet [91]
The magnitude of the force<span> a 1.5 x 10-3 C charge exerts on a 3.2 x 10-4 C charge located 1.5 m away is 1920 Newtons. The formula used to solve this problem is:

F = kq1q2/r^2

where:
F = Electric force, Newtons
k = Coulomb's constant, 9x10^9 Nm^2/C^2
q1 = point charge 1, C
q2 = point charge 2, C
r = distance between charges, meters

Using direct substitution, the force F is determined to be 1920 Newtons.</span>
7 0
2 years ago
Bill leaves his 60 W desk lamp on every day, including weekends, for eight hours. After one month (30 days), how much total ener
maxonik [38]

' W ' is the symbol for 'Watt' ... the unit of power equal to 1 joule/second.

That's all the physics we need to know to answer this question.
The rest is just arithmetic.

(60 joules/sec) · (30 days) · (8 hours/day) · (3600 sec/hour)

= (60 · 30 · 8 · 3600) (joule · day · hour · sec) / (sec · day · hour)

= 51,840,000 joules
__________________________________

Wait a minute !  Hold up !  Hee haw !  Whoa ! 
Excuse me.  That will never do.
I see they want the answer in units of kilowatt-hours (kWh).
In that case, it's

(60 watts) · (30 days) · (8 hours/day) · (1 kW/1,000 watts)

= (60 · 30 · 8 · 1 / 1,000) (watt · day · hour · kW / day · watt)

= 14.4 kW·hour

Rounded to the nearest whole number:

14 kWh

7 0
2 years ago
Machine movement can be divided into what two main categories?
Ivenika [448]

Answer:

1.) Employee Driven Machines

2.) Self Driven Machines

Explanation:

A machine is a mechanical device that utilizes the application of forces to carry out an operation. It's operation can be "employee driven" (i.e it is operated by a person) or "self driven" (i.e it is operated by itself).

3 0
2 years ago
Read 2 more answers
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