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andrew-mc [135]
3 years ago
9

Engineers who design battery-operated devices such as cell phones and MP3 players try to make them as efficient as possible. An

engineer tests a cell phone and finds that the batteries supply 10,000 J of energy to make 5500 J of output energy in the form of sound and light for the screen. How efficient is the phone?
Physics
1 answer:
Svetradugi [14.3K]3 years ago
5 0


efficiency= [useful energy transferred ÷ total energy supply]×100%

So, [5500÷10000]×100%=0.55×100

                                        =55%

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A Meteorite Strikes On October 9, 1992, a 27-pound meteorite struck a car in Peekskill, NY, leaving a dent 22 cm deep in the tru
vagabundo [1.1K]

Answer:

Acceleration of the meteorite, a=-38409.09\ m/s^2

Explanation:

It is given that,

A Meteorite after striking struck a car, v = 0

Initial speed of the Meteorite, u = 130 m/s

Distance covered by Meteorite, s = 22 cm = 0.22 m

We need to find the magnitude of its deceleration. It can be calculated using the third equation of motion as :

a=\dfrac{v^2-u^2}{2s}

a=\dfrac{-(130)^2}{2\times 0.22}

a=-38409.09\ m/s^2

So, the deceleration of the Meteorite is -38409.09\ m/s^2. Hence, this is the required solution.

7 0
2 years ago
A student starts a food fight by throwing a 0.5 kg burrito at some girl he likes. He throws it kind-of hard so he accelerates it
Elenna [48]

Explanation:

m = mass of burrito thrown by the student = 0.5 kg

a = acceleration of the burrito thrown by the student = 3 m/s²

F = force applied by the student on the burrito = ?

According to newton's second law , the net force on an object is the product of its mass and acceleration. it is given as

F = ma

inserting the values

F = (0.5) (3)

F = 1.5 N

hence the net force on the burrito comes out to be 1.5 N

4 0
2 years ago
An example of convection and conduction within a BBQ. I also accept diagrams but please write honestly or I will report.
qwelly [4]
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7 0
3 years ago
What is the speed of alpha rays, beta rays and gamma rays ?
Leya [2.2K]
Alpha particles are released by proton rich unstable nuclei. It has no electrons to balance the protons making it positively charged particles moving at very high speeds. Gamma articles are electromagnetic waves of short wavelength and high frequency. It has a speed same as the speed of light. Beta particles are released by neutron rich unstable nuclei. It has a speed of less than the gamma particles.
5 0
2 years ago
The spraying of pesticides can be carefully planned, but accidents, weather conditions that could not be foreseen, and pilot err
12345 [234]

Answer:

B) weather conditions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than

Explanation:

Option B obeys the principle of parallelism because the two phrases, " can be carefully planned" and "cannot be foreseen" follow the same grammatical structure. Option A does not obey parallelism because " can be carefully planned" and "could not be foreseen" do not follow the same grammatical structure.

The phrase " they had anticipated" in the other options apart from B do not have a matching subject. Pilot errors is the subject in this sentence and it is not expected to anticipate anything, only the pilots can.

Moreover, "that cannot be foreseen" is more parallel to "can be carefully planned" that "unforeseeable" or "foreseeable" used in the other options

6 0
3 years ago
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