F=K*X,
F=M*a

M*a=K*X

2.5*9.81=K*0.0276

24.525=K*0.0276

24.525/0.0276=K

K= 888.6 N/m ---- force constant

assuming 2.5 refers to the new extension, just divide F/ 0.025
to get

981N/m

8 0

4 years ago

Reading glasses with a power of 1.50 diopters make reading a book comfortable for you when you wear them 1.8 cmcm from your eye.

Vlad1618 [11]

Answer:

The near point is $n =44.8 \ cm$

Explanation:

From the question we are told that

The power is $P = 1.50$

The distance from the eye is $k = 1.8 \ cm$

The distance of the book from the eye is $z = -28 \ cm$

Generally the focal length of the glasses is

$f = \frac{1}{P}$

=> $f = \frac{1}{1.50 }$

=> $f = 0.667 \ m$

=> $f = 66.7 \ cm$

The object distance is evaluated as

$u = z + k$

=> $u = -28 + 1.8$

=> $u = -26.2 \ cm$

The image distance is evaluated from lens formula as

$\frac{1}{v} = \frac{1}{f} + \frac{1}{u}$

=> $\frac{1}{v} = \frac{1}{66.7} + \frac{1}{-26.2}$

=> $v=- \frac{1}{0.0232}$

=> $v=- 43 \ cm$

The near point is evaluated as

$n = -v + k$

=> $n =-(-43) + 1.8$

=> $n =44.8 \ cm$

3 0

3 years ago

Count the dots to make sure that all of the valence electrons are represented 2

Semenov [28]

Do you have a diagram or anything?

5 0

4 years ago