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
kodGreya [7K]
3 years ago
9

A 20-cm-diameter disk emits light uniformly from its surface. 40 cm from this disk, along its axis, is a 16.0-cm-diameter opaque

black disk; the faces of the two disks are parallel. 40 cm beyond the black disk is a white viewing screen. The lighted disk illuminates the screen, but there's a shadow in the center due to the black disk. What is the diameter of the completely dark part of this shadow
Physics
1 answer:
Marianna [84]3 years ago
7 0

Answer:

132

Explanation:

if you round it is correct

You might be interested in
___ is produced when grains of quartz in sandstone are welded together when the rock is subjected to high temperatures.
Galina-37 [17]
Quartzite is produced when grains of quartz in sandstone are welded together when the rock is subjected to high temperatures.  Quartzite<span> or Quarzit is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. </span><span>It is formed when a quartz-rich sandstone is altered by the heat, pressure, </span>
3 0
3 years ago
physics a flower pot falls from a windowsill 25.0m above the sidewalk. how much time does a passerby on the sidewalk below have
Usimov [2.4K]
v_f^2 = v_0^2 + 2*a*d
Since the flower pot is dropped, it has an initial velocity of zero. Also the flower pot accelerates due to gravity.

so

v_f = \sqrt{2*g*d}=\sqrt{2*9.81*25.0}
8 0
3 years ago
Two small objects each with a net charge of +Q exert a force of magnitude F on each other. We replace one of the objects with an
Alona [7]

Answer:

F'= 4F/9

Explanation:

Two small objects each with a net charge of +Q exert a force of magnitude F on each other. If r is the distance between them, then the force is given by :

F=\dfrac{kQ^2}{r^2} ...(1)

Now, if one of the objects with another whose net charge is + 4Q is replaced and also the distance between +Q and +4Q charges is increased 3 times as far apart as they were. New force is given by :

F'=\dfrac{kQ\times 4Q}{(3r)^2}\\\\F'=\dfrac{4kQ^2}{9r^2}.....(2)

Dividing equation (1) and (2), we get :

\dfrac{F}{F'}=\dfrac{\dfrac{kQ^2}{r^2}}{\dfrac{4kQ^2}{9r^2}}\\\\\dfrac{F}{F'}=\dfrac{kQ^2}{r^2}\times \dfrac{9r^2}{4kQ^2}\\\\\dfrac{F}{F'}=\dfrac{9}{4}\\\\F'=\dfrac{4F}{9}

Hence, the correct option is (d) i.e. " 4F/9"

7 0
3 years ago
During a medieval siege of a castle, the attacking army uses a trebuchet to heavy stones at the castle the trebuchet launches th
vlada-n [284]

Answer:

Explanation:

The question relates to time of flight of a projectile .

Time of flight = 2 u sinθ / g

u is speed of projectile , θ is angle of projectile

= 2 x 48.5 sin42 / 9.8

= 6.6 seconds  .

Maximum height attained

= u² sin²θ / g

= 48.5² sin²42 / 9.8

= 107.47 m .

7 0
3 years ago
An eight-turn coil encloses an elliptical area having a major axis of 40.0 cm and a minor axis of 30.0 cm. The coil lies in the
Darina [25.2K]

Answer:

9.25 x 10^-4 Nm

Explanation:

number of turns, N = 8

major axis = 40 cm

semi major axis, a = 20 cm = 0.2 m

minor axis = 30 cm

semi minor axis, b = 15 cm = 0.15 m

current, i = 6.2 A

Magnetic field, B = 1.98 x 10^-4 T

Angle between the normal and the magnetic field is 90°.

Torque is given by

τ = N i A B SinФ

Where, A be the area of the coil.

Area of ellipse, A = π ab = 3.14 x 0.20 x 0.15 = 0.0942 m²

τ = 8 x 6.20 x 0.0942 x 1.98 x 10^-4 x Sin 90°

τ = 9.25 x 10^-4 Nm

thus, the torque is 9.25 x 10^-4 Nm.

5 0
3 years ago
Other questions:
  • How do mass and speed affect kinetic energy?
    12·1 answer
  • A roller coaster car starts at a height of 90 M at Point a and is moving at a speed of 20 m per second on a later Hill at Point
    12·2 answers
  • The position of a ball as a function of time is given by
    9·1 answer
  • The answer pleaseeeeeee
    9·1 answer
  • Which theory of light is the photon more consistent with
    6·1 answer
  • A circuit has a voltage drop of 12 V across a 30 2 resistor that carries a
    6·2 answers
  • Jupiter, the largest planet in the solar system, has an equatorial radius of about 7.1 x 10^4km (more than 10 times that of Eart
    13·1 answer
  • As a red of recent weather activity, there’s less water available for human consumption. Which blome is affected by the most by
    14·1 answer
  • 5. Graph A below plots a race car's speed for 5 seconds. The car's rate of acceleration is 6 m/s^2
    15·1 answer
  • Future space rockets might propel themselves by firing laser beams, rather than exhaust gases, out the back. The acceleration wo
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!