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3 years ago

What is principal focus and focus length with examples

Physics

1 answer:

Shkiper50 [21]3 years ago

7 0

Explanation:

Principle focus is the point on the axis of a convex lens, where the parallel rays of light from one side of the lens. meet on other side after refraction. Distance between optical centre to principle focus point is the focal length.

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a flag of mass 2.5 kg is supported by a single rope. A strong horizontal wind exerts a force of 12 N on the flag. Calculate the

tatuchka [14]

The free-body diagram of the forces acting on the flag is in the picture in attachment.

We have: the weight, downward, with magnitude
$W=mg = (2.5 kg)(9.81 m/s^2)=24.5 N$
the force of the wind F, acting horizontally, with intensity
$F=12 N$
and the tension T of the rope. To write the conditions of equilibrium, we must decompose T on both x- and y-axis (x-axis is taken horizontally whil y-axis is taken vertically):
$T \cos \alpha -F=0$
$T \sin \alpha -W=$
By dividing the second equation by the first one, we get
$\tan \alpha = \frac{W}{F}= \frac{24.5 N}{12 N}=2.04$
From which we find
$\alpha = 63.8 ^{\circ}$
which is the angle of the rope with respect to the horizontal.

By replacing this value into the first equation, we can also find the tension of the rope:
$T= \frac{F}{\cos \alpha}= \frac{12 N}{\cos 63.8^{\circ}}=27.2 N$

7 0

3 years ago

100 joule of heat produced each 1 secomd on 4ohm find the potential difference

irakobra [83]

Answer:

20 V

Explanation:

Power is 100 J/s or 100 W.

We know that P = IV = $\frac{V^{2} }{R}$ .

Isolate the potential difference. V = $\sqrt{RP}$ = $\sqrt{100 * 4}$ = 20 V

8 0

3 years ago

2 forces are acting on a body. I forgot the body doesn't it's position or shape, the forces.......a)must be of equal magnitude b

Veseljchak [2.6K]

Answer:

Explanation:

only if there is a net force of zero, the body will not move

some people may say B but that is wrong because maybe one force is greater than the other so the object would still move even though the forces are in opposite directions and parallel

5 0

3 years ago

The 6 strings on a guitar all have about the same length and are stretched with about the same tension.The highest string vibrat

ahrayia [7]

Answer:

B. d(low)=4d(high)

Explanation:

Frequency of a string can be written as;

f = v/2L

Where;

v = sound velocity

L = string length

Frequency can be further expanded to;

f = v/2L = (1/2L)√(T/u) ......1

Where;

m= mass,

u = linear density of string,

T = tension

p = density of string material

A = cross sectional area of string

d = string diameter

u = m/L .......2

m = pAL = p(πd^2)L/4 (since Area = (πd^2)/4)

f = (1/2L)√(T/u) = (1/2L)√(T/(m/L))

f = (1/2L)√(T/((p(πd^2)L/4)/L))

f = (1/2L)√(4T/pπd^2)

f = (1/L)(1/d)√(4T/pπ)

Since the length of the strings are the same, the frequency is inversely proportional to the string diameter.

f ~ 1/d

So, if

4f(low) = f(high)

Then,

d(low) = 4d(high)

6 0

3 years ago

Ivan pushes a dresser with full drawers across his carpeted floor. What could Ivan do to reduce the amount of friction between t

aniked [119]

Answer:

Place some smooth tiles under the dresser

Smooth surfaces, like smooth tile, are easy to slide over. They create very little friction. Rough surfaces like carpet create much more friction.

remove the drawers from the dresser

Weight affects friction in that friction is directly proportional to the weight of the load one is moving. So reduce the weight, reduce the friction.

Explanation:

Speed does not impact friction, so moving the dresser slower won't help. Wind has nothing to do with the scenario, so that's not a correct option.

7 0

2 years ago

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What is principal focus and focus length with examples​

What is principal focus and focus length with examples