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inysia [295]
3 years ago
8

The near point of an eye is 48.5 cm. A corrective lens is to be used to allow this eye to focus clearly on objects at the distan

ce of the healthy near point. What should be the focal length of this lens
Physics
1 answer:
Masteriza [31]3 years ago
3 0

Answer:

The focal length of the lens should be -51.5 cm (a concave lens).

Explanation:

The purpose of the lens is to make objects at 48.5 cm appear at the healthy near point. The healthy near point is 25.0 cm.

We use the lens formula

\dfrac{1}{f} = \dfrac{1}{u} + \dfrac{1}{v}

where <em>f</em> = focal length, <em>u</em> = object distance and <em>v</em> = image distance.

In this case, <em>u</em> = 48.5 cm and <em>v</em> = -25.0 cm.

<em>v</em> is negative because the image is virtual an not real. (Here, we are using the real-is-positive sign convention)

\dfrac{1}{f} = \dfrac{1}{48.5} + \dfrac{1}{-25.0} = -\dfrac{23.5}{1212.5}

f = -51.5

The negative sign indicates the lens is concave.

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UNO [17]

Answer:

Newton's second law of motion

Explanation:

Newton's second law of motion can be stated  

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in another form,

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5 0
3 years ago
Which of the following electrical components is a temporary electrical energy storage device?
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Answer:

A capacitor

Explanation:

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Hope this helps! :)

6 0
3 years ago
Wilma can mow a lawn in 80 minutes. Rocky can mow the same lawn in 120 minutes. Construct an equation that would allow you to de
xeze [42]

Answer:

t = 96 minutes

Explanation:

Time to mow 1 lawn by Wilma is 80 minutes

so work done in 1 minute by Wilma is given as

W_1 = \frac{1}{80}

Similarly Rocky mow same lawn in 120 minute

so work done in 1 minute by Rocky is given as

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now we know that they both worked by "t" time

so total work performed by them

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they both mow 2 lawns then it is given as

2 = (\frac{1}{80} + \frac{1}{120})t

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3 years ago
Ms. Kasper is in a panic. Her cat, Penny, is stuck in a tree and about to jump out. In order to save her cat, Ms. Kasper needs t
Misha Larkins [42]

Answer:

Speed greater than 4 m/s

Explanation:

Given that Ms. Kasper is in a panic. Her cat, Penny, is stuck in a tree and about to jump out. In order to save her cat, Ms. Kasper needs to run to the tree, 12 meters away. If it takes her cat, 3 seconds to fall, how fast would Ms. Kasper have to run to save her cat?

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Speed = 4 m/s

Ms Kasper must run at speed more than 4m/s for her to save the cat.

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3 years ago
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Oliga [24]
To answer this question, you need to know the definition of Relative Motion:
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3 years ago
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