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3 years ago

What causes short sightedness ?how is it corrected

Physics

1 answer:

7nadin3 [17]3 years ago

5 0

Answer:

Short sight occurs when the eyeball is too long or the lens is too thick, or both. As a result, light rays from distant objects are focused in front of the retina (because the light rays are highly converged). The image formed on the retina is therefore out of focus.

Short sight can be corrected by wearing glasses with concave lenses. Light rays from distant objects are diverged by concave lenses before entering the eyes, so that light can be focused on the retina to form a sharp image.

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A box is being pulled to the right on flat ground with a force of 112 N at an angle of 42° to the horizontal. What is the x-comp

sasho [114]

The x-component is related with the Force through the trigonometric function cosine.

cos(42°) = x-component / F ⇒ x-component = Fcos(42°) = 112N*0.743 = 83.2 N

4 0

3 years ago

Two devices with capacitances of 25 μf and 5.0 μf are each charged with separate 120 v power supplies. calculate the total energ

mash [69]

The energy stored in a capacitor is given by
$U= \frac{1}{2} CV^2$
where C is the value of the capacitance while V is the voltage difference applied to the capacitor.

Let's calculate the energy of the first capacitor:
$U_1 = \frac{1}{2} (25\cdot 10^{-6}F)(120 V)=1.5 \cdot 10^{-3}J$

And now the energy of the second capacitor:
$U_2 = \frac{1}{2} (5 \cdot 10^{-6}F)(120 V)=3 \cdot 10^{-4}J$

So, the total energy stored in the two capacitors is
$U=U_1 +U_2 = 1.8 \cdot 10^{-3}J$

3 0

3 years ago

Read 2 more answers

A concave mirror has a radius of curvature of 10 cm. Find the location an height of the image if the distance of the object is 8

puteri [66]

R=10
F=R/2
F=10/2=5
F=-5(CONCAVE MIRROR)
U=-8(CONCAVE MIRROR)
HEIGHT OF OBJECT=1.5
V=?
HEIGHT OF IMAGE=?
I/F=1/U+1/V
-I/5=-1/8-1/V
-1/V=-1/5+1/8
-1/V=-8+5/40
-1/V=-3/40
1/V=3/40
V=40/3

HEIGHT OF IMAGE/HEIGHT OF OBJECT =-V/U
HEIGHT OF IMAGE=40/3*1/-8*15/10
=-20/8
=-2.5

7 0

3 years ago

Students are using the experimental setup shown in the image in which the two ends of a string are attached to a car and to a ha

AlekseyPX

The Newton's second law and kinematics allows to find the result of the error when placing the masses in the car is:

Acceleration decreases.

The plot of position vs. time squared is still linear, but the slope is less.

Newton's second law gives a relationship between the net force, mass and acceleration of the body

F = ma

a = $\frac{F}{m}$

Where F is the force, m the mass and the acceleration

Kinematics studies the motion of bodies, looking for relationships between position, velocity, and acceleration.

x = v₀ t + ½ a t²

In the experiment, the position and time of the car are measured, starting from rest in each experiment.

x = ½ a t²

Let's substitute

x = ½ ( $\frac{F}{m}$ ) t²

This is the equation that the students should graph, a graph of the position versus time squared can be made to obtain a line.

The slope of the line is the acceleration of the car, which is related to the force that is the weight of the hanging mass.

When the student makes the mistake of placing the mass on the car, the acceleration decreases therefore in a graph the position values are smaller for each time.

The linearity of the graph is maintained, but when calculating the slope it gives lower values.

In conclusion using Newton's second law and kinematics we can find the result of the error when placing the masses on the car is:

Acceleration decreases.

The plot of position vs. time squared is still linear, but the slope is less.

Learn more here: brainly.com/question/11298125

7 0

3 years ago

Read 2 more answers

According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of wate

WARRIOR [948]

Answer:

Explanation:

Given:

1 can of concentrate requires 3 cans of water

Now,

Total ounces in 200 6-ounce cans = 1200 ounces

also,

for 1 can of concentrate requires 3 cans of water

thus,

for 12 ounces can water can required = 3 × 12 ounces = 36 ounces of cans

Thus,

total ounce of juice per can = 12 + 36 = 48 ounces per can

therefore,

the number of 12-ounce cans required are = $\frac{\textup{Ttoal ounces}}{\textup{Ounces per can}}$

= $\frac{\textup{1200}}{\textup{48}}$

the number of 12-ounce cans required are = 25

8 0

4 years ago