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jarptica [38.1K]
3 years ago
8

supposed to vacuum cleaner uses 120 J of electrical energy. If 45 J used to pull air into a vacuum cleaner, how efficient is the

vacuum cleaner?
Physics
2 answers:
Phoenix [80]3 years ago
8 0

Answer:

The efficiency of the vacuum cleaner is 37.5%

Explanation:

The efficiency of a machine can be calculated as

Efficiency = (work output ÷ work input) × 100%

Work output (according to the question) is 45J of electrical energy

work input (according to the question) is 120J of electrical energy

Efficiency = (45 ÷ 120) × 100

Efficency = 37.5 %

The efficiency of the vacuum cleaner is 37.5%

NOTE: Vacuum cleaner is a machine and a machine can not be 100% efficient

Ainat [17]3 years ago
4 0

we know that

Power efficiency is defined as the ratio of the output power divided by the input power:

so

efficiency =\frac{ Power\  out}{Power\  in} *100

in this problem

Power\  out=45J\\ Power\  in=120J

Substitute in the formula above

efficiency =\frac{ 45}{120} *100

efficiency =37.5%

therefore

the answer is

the efficient is 37.5%

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When you stretch a spring 13 cm past its natural length, it exerts a force of 21
zloy xaker [14]

Answer:

A. 1.6 N/cm

Explanation:

spring constant = 21/13 = 1.6 N/cm

8 0
3 years ago
(help please no links )
trapecia [35]

Answer:

Hello, how's your day going?

if humanity came together and made a base on the moon, it would be revolutionary. The point of a base on the moon would have multiple purposes. for example, some think that the moon contains valuable metals such as iron and titanium. a base would serve as a place for workers harvesting metals to rest. Obviously or not most of the iron harvesting would be done automatically by robots and such.

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Hope it helped

Spiky Bob

5 0
3 years ago
35. An object of mass m moving at speed v0 strikes an object of mass 2m which had been at rest. The first object bounces backwar
MAVERICK [17]

Answer:

The collision is not elastic. The system increases his kinetic energy m*v₀² times.

Explanation:

Assuming no external forces acting during the collision, total momentum must be conserved.

Considering the information provided, we can write the momentum conservation equation as follows:

m*v₀ = -m*v₀ + 2*m*vf

Solving for vf, we arrive to this somehow surprising result:

vf = v₀ (in the same direction that m was moving before the collision).

In order to determine if the collision was elastic, or not, we need to calculate the kinetic energy of the system before and after the collision:

K₀ = 1/2*m*v₀²

Kf = 1/2*m*v₀² (due to the object of mass m, as the kinetic energy is always positive) + 1/2 (2m) * v₀²

⇒Kf = 1/2*m*v₀² + 1/2 (2m) * v₀² = 3/2*m*v₀²

ΔK = Kf - K₀ = 3/2*m*v₀² - 1/2*m*v₀² = m*v₀²

As there is a net difference between the final and initial kinetic energies, and the total kinetic energy must be conserved in an elastic collision (by definition) we conclude that the collision is not elastic, and the change in the kinetic energy of the system is equal to m*v₀².

5 0
3 years ago
Have properties that are in between metals and nonmetals.
andrew-mc [135]

Answer:

metalloids

Explanation:

metalloids are also known as semiconductors. they are the ones that are between metals and non metals

3 0
3 years ago
12. A measuring cylinder has 150ml. of water in it. When a stone is immersed into the measuring cylinder, the water level raised
skelet666 [1.2K]

Answer:

60ml

Explanation:

I'm going to assume you mean 210ml not centimeters. To find the volume all we do is subtract both values or with the formula [ f - i = v ]  where f = final amount and i = initial amount.

210 - 150 = 60ml

Best of Luck!

4 0
3 years ago
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