1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
liq [111]
3 years ago
15

A machinist with normal vision has a near point at 25 cm. The machinist wears eyeglasses in order to do close work. The power of

the lenses is +1.75 diopters. With these eyeglasses, what is the near point of the machinist?
Physics
1 answer:
Alik [6]3 years ago
7 0

Answer:

17.4 cm

Explanation:

Power of lens = +1.75 diopters

Focal length of lens

f=\frac{100}{1.75}=\frac{400}{7}

This is a convex lens as focal the diopter given is positive which makes the focal length positive. Image distance will be negative.

v = -25

\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\\\Rightarrow \frac{1}{-25}-\frac{1}{u}=\frac{1}{\frac{400}{7}}\\\Rightarrow -\frac{1}{u}=\frac{7}{400}+\frac{1}{25}\\\Rightarrow \frac{1}{u}=-\frac{7}{400}-\frac{1}{25}\\\Rightarrow \frac{1}{u}=-0.0575\\\Rightarrow u=-17.4\ cm

∴ The new near point is 17.4 cm

You might be interested in
A bowling ball encounters a 0.760-m vertical rise on the way back to the ball rack, as the drawing illustrates. ignore frictiona
Blizzard [7]
I just solved similar type of question. You can refer to my solution which I have attached

8 0
2 years ago
Now let’s apply the work–energy theorem to a more complex, multistep problem. In a pile driver, a steel hammerhead with mass 200
andrew11 [14]

Answer:

a) v = 7.67

b) n = 81562 N

Explanation:

Given:-

- The mass of hammer-head, m = 200 kg

- The height at from which hammer head drops, s12 = 3.00 m

- The amount of distance the I-beam is hammered, s23 = 7.40 cm

- The resistive force by contact of hammer-head and I-beam, F = 60.0 N

Find:-

(a) the speed of the hammerhead just as it hits the I-beam and

(b) the average force the hammerhead exerts on the I-beam.

Solution:-

- We will consider the hammer head as our system and apply the conservation of energy principle because during the journey of hammer-head up till just before it hits the I-beam there are no external forces acting on the system:

                                   ΔK.E = ΔP.E

                                  K_2 - K_1 = P_1- P_2

Where,  K_2: Kinetic energy of hammer head as it hits the I-beam

             K_1: Initial kinetic energy of hammer head ( = 0 ) ... rest

             P_2: Gravitational potential energy of hammer head as it hits the I-beam. (Datum = 0)

             P_1: Initial gravitational potential energy of hammer head      

- The expression simplifies to:

                                K_2 = P_1

Where,                     0.5*m*v2^2 = m*g*s12

                                v2 = √(2*g*s12) = √(2*9.81*3)

                                v2 = 7.67 m/s

- For the complete journey we see that there are fictitious force due to contact between hammer-head and I-beam the system is no longer conserved. All the kinetic energy is used to drive the I-beam down by distance s23. We will apply work energy principle on the system:

                               Wnet = ( P_3 - P_1 ) + W_friction

                               Wnet = m*g*s13 + F*s23

                               n*s23 = m*g*s13 + F*s23

Where,    n: average force the hammerhead exerts on the I-beam.

               s13 = s12 + s23

Hence,

                             n = m*g*( s12/s23 + 1) + F

                             n = 200*9.81*(3/0.074 + 1) + 60

                             n = 81562 N

                               

                                                   

6 0
3 years ago
Which object represents a negatively charged particle? which object represents a positively charged molecule? which object repre
kari74 [83]

The answers to your questions are as written below:

  • The objects that represents a negatively charged particle is : Image B
  • The object that represents a positively charged molecule is : Image A
  • The object that represents an uncharged molecule is : Image C
  • The object the will not move when in an electric fied is : Image C

<h3>Different types of charges molecules</h3>

A negatively charged molecule move inwards when placed in an electric field while positively charged molecule placed in a electric field will move outwards the electric field.

A neutral/uncharged molecule will remains still when placd in an elctric field due to the absence of charges.

Hence we can concude that the answers to your questions are as listed above.

Learn more about electric charges :brainly.com/question/857179

#SPJ4

attached below is the missing image

8 0
2 years ago
PLEASE HELP ASAP! THANKS!<br><br> Why is it a rare occasion to see a solar eclipse from your home?
Y_Kistochka [10]

Answer:

It is very rare to see a solar eclipse from your home, because the Earth, Sun, and the moon need to align just right.  Not everyone in the world can view a solar eclipse, only some area can.  A solar eclipse is where the moon blocks out the sun.  If you think about it:  Let's say you live in Florida, U.S.A.  You may see the moon coming in front of the sun, but if you lived in California or sumthin', the moon and the sun wouldn't be aligned to form a solar eclipse.  It all depends on location... so it is rare to see one.

5 0
3 years ago
The 9-inch-long elephant nose fish in the Congo River generates a weak electric field around its body using an organ in its tail
Alik [6]

Answer:

1.34\cdot 10^{-16} C

Explanation:

The strength of the electric field produced by a charge Q is given by

E=k\frac{Q}{r^2}

where

Q is the charge

r is the distance from the charge

k is the Coulomb's constant

In this problem, the electric field that can be detected by the fish is

E=3.00 \mu N/C = 3.00\cdot 10^{-6}N/C

and the fish can detect the electric field at a distance of

r=63.5 cm = 0.635 m

Substituting these numbers into the equation and solving for Q, we find the amount of charge needed:

Q=\frac{Er^2}{k}=\frac{(3.00\cdot 10^{-6} N/C)(0.635 m)^2}{9\cdot 10^9 Nm^2 C^{-2}}=1.34\cdot 10^{-16} C

4 0
2 years ago
Other questions:
  • What should be the spring constant k of a spring designed to bring a 1200 kg car to rest from a speed of 85 km/h so that the occ
    12·1 answer
  • An unstable nucleus results from too many or too few A) electrons. B) neutrons. C) protons. D) radons.
    8·1 answer
  • The hydrocarbon C2H4 is a member of the_series.
    7·2 answers
  • Assume (unrealistically) that a TV station acts as a point source broadcasting isotropically at 3.2 MW. What is the intensity of
    9·1 answer
  • Three resistances 2 ohm ,3ohm and 5 ohm are connected in parallel and a
    14·1 answer
  • A circuit has a current of 1.2 A. If the voltage decreases to one-third of its original amount while the resistance remains
    11·1 answer
  • 5/6 - 1/3 sorry for add part i was meant to do minus but tell me what it is?​
    10·2 answers
  • What is shown in the diagram? A). A turbine B). An electromagnet C). A motor D). A generator
    6·1 answer
  • What would the current be for a circuit that has a voltage of 0.8 V and a resistance of 0.01 Q?
    11·1 answer
  • Suggest a form of renewable energy that could be used to power an electric ticket machine that only needs to work during dayligh
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!