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
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.

You might be interested in
When you jump straight up as high as you can, what is the order of magnitude of the maximum recoil speed that you give to the Ea
Klio2033 [76]

Answer:

5.66 × 10⁻²³ m/s

Explanation:

If i assume i can jump as high as h = 2 m, my initial velocity is gotten from v² = u² + 2gh. Since my final velocity v = 0, u = √2gh = √(2 × 9.8 × 2) = √39.2 m/s = 6.26 m/s.

Since initial momentum = final momentum,

mv₁ + MV₁ = mv₂ + MV₂ where m, M, v₁, V₁, v₂ and V₂ are my mass, mass of earth, my initial velocity, earth's initial velocity, my final velocity and earth's final velocity respectively.

My mass m = 54 kg, M = 5.972 × 10²⁴ kg, v₁ = 6.26 m/s, V₁ = 0, v₂ = 0 and V₂ = ?

So mv₁ + M × 0 = m × 0 + MV₂

mv₁ = MV₂

V₂ = mv₁/M =  54kg × 6.26 m/s/5.972 × 10²⁴ kg = 338.093/5.972 × 10²⁴ = 56.61 × 10⁻²⁴ m/s = 5.661 × 10⁻²³ m/s ≅ 5.66 × 10⁻²³ m/s

5 0
3 years ago
Please help my test is going on. Please answer both (i) and (ii). ​
Eduardwww [97]

Answer:

i. 7.5 m

ii. 15000 N

Explanation:

Area under vt graph shows the displacement

so area of triangle ABE= 1/2×15×2

=7.5 m

ii) F=ma

here, m=1000kg

and a=v-u/t

=15-0/1

a=15

F=1000×15=15000N

8 0
3 years ago
A school track team member ran for a total of 15.85 miles in practice over 5 days. How many miles did he average per day?
liraira [26]

{\underline{\pink{\textsf{\textbf{ Answer : }}}}}

➡ 15.85/5

➡ 3.17 ans.

6 0
3 years ago
You set a tuning fork into vibration at a frequency of 723 Hz and then drop it off the roof of the Physics building where the ac
zaharov [31]

Answer:

Explanation:

Given

Original Frequency f=723\ Hz

apparent Frequency f'=697\ Hz

There is change in frequency whenever source move relative to the observer.

From Doppler effect we can write as

f'=f\cdot \frac{v-v_o}{v+v_s}

where  

f'=apparent frequency  

v=velocity of sound in the given media

v_s=velocity of source

v_0=velocity of observer  

here v_0=0

697=723\cdot (\frac{343-0}{343+v_s})

v_s=(\frac{f}{f'}-1)v

v_s=(\frac{723}{697}-1)\cdot 343

v_s=12.79\approx 12.8\ m/s

i.e.fork acquired a velocity of 12.8 m/s

distance traveled by fork is given by

v^2-u^2=2as

where v=final velocity

u=initial velocity

a=acceleration

s=displacement

v_s^2-0=2\times 9.8\times s

s=\frac{12.8^2}{2\times 9.8}

s=8.35\ m

                                       

5 0
3 years ago
A 3.89 x 10-8 F capacitor has a
alexira [117]

Answer:

.00295629

Explanation:

Acellus

6 0
2 years ago
Other questions:
  • A 7-hp (shaft) pump is used to raise water to an elevation of 19 m. if the mechanical efficiency of the pump is 82 percent, dete
    12·1 answer
  • Calculate the average speed (in m/s) of a car that travels 50km in 30 minutes.
    15·1 answer
  • Why do astronauts appear to move in slow motion in space?
    13·1 answer
  • How is the motion of particles in a liquid different from the motion of particles in a solid?
    13·1 answer
  • An ideal monatomic gas expands from an initial pressure and volume of 32 atm and 1.0 L to a final volume of 4.0 L. The initial t
    10·1 answer
  • A positive charge, q1, of 5 µC is 3 × 10–2 m west of a positive charge, q2, of 2 µC. What is the magnitude and direction of the
    14·2 answers
  • "Two point charges exert a 6.50 N force on each other. What will the force (in N) become if the distance between them is increas
    6·1 answer
  • When the area over which pressure is applied is increased,
    6·1 answer
  • Clara made a chart to summarize some of the evidence that supports the big bang theory.
    12·2 answers
  • 8. Placing your vehicle between the pilot/escort vehicle and an oversize/overweight vehicle can be dangerous.A. TrueB. False
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!