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Alla [95]
3 years ago
5

A light ray in air enters and passes through a block of glass. What can be stated with regard to its speed after it emerges from

the block? Speed is less than when in glass. Speed is less than before it entered glass. Speed is same as that in glass. Speed is same as that before it entered glass.

Physics
1 answer:
Alik [6]3 years ago
6 0

Answer:

Speed is same as that before it entered glass.

Explanation:

Given:

A light ray enters and passes through the glass as shown in the diagram.

We have to analyze its speed.

Speed of light in air is 3\times 10^8\ ms^-^1 and speed of light in glass is 2.25\times 10^8\ ms^-^1

Whenever a light ray enters a glass block or slab there is bending of light at the interface of the two media.

So speed of light will decrease in glass medium and again it passes to the air.

So

Speed of light in air will again increase or will be equivalent to the earlier speed when it was entering the glass block.

Finally

Speed is same as that before it entered glass as it in the same medium (air).

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A tennis ball is released from a height of 4.0 m above the floor. After its third bounce off the floor, it reaches a height of 1
diamong [38]

Answer:

The percentage of its mechanical energy does the ball lose with each bounce is 23 %

Explanation:

Given data,

The tennis ball is released from the height, h = 4 m

After the third bounce it reaches height, h' = 183 cm

                                                                       = 1.83 m

The total mechanical energy of the ball is equal to its maximum P.E

                                      E = mgh

                                          = 4 mg

At height h', the P.E becomes

                                      E' = mgh'

                                           = 1.83 mg

The percentage of change in energy the ball retains to its original energy,

                                 \Delta E\%=\frac{1.83mg}{4mg}\times100\%

                                  ΔE % = 45 %

The ball retains only the 45% of its original energy after 3 bounces.

Therefore, the energy retains in each bounce is

                                   ∛ (0.45) = 0.77

The ball retains only the 77% of its original energy.

The energy lost to the floor is,

                                E = 100 - 77

                                   = 23 %

Hence, the percentage of its mechanical energy does the ball lose with each bounce is 23 %      

5 0
3 years ago
A block is released from rest, at a height h, and allowed to slide down an inclined plane. There is friction on the plane. At th
GREYUIT [131]

Here the block has two work done on it

1. Work done by gravity

2. Work done by friction force

So here it start from height "h" and then again raise to height hA after compressing the spring

So work done by the gravity is given as

W_g = m_A g(h - h_A)

Now work done by the friction force is to be calculated by finding total path length because friction force is a non conservative force and its work depends on total path

W_f = -(\mu m_A g cos\theta)(\frac{h}{sin\theta} + \frac{h_A}{sin\theta})

W_f = -\mu m_A g cot\theta(h + h_A)

Total work done on it

W = m_A g(h - h_A) - \mu m_A g cot\theta(h + h_A)

So answer will be

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Being that Alaska is a state, it should be capitalized. You always capitalize a state name
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3 years ago
The value of a car after 5 years is a quantitative data. True or False
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Harrizon [31]

Answer:

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The resistance of the wire is directly proportional to the length of the wire. As the wire is cut into 8 equal pieces so the resistance of small wire is R/8.

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The equivalent resistance is given by

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R_{eq}=\frac{R}{64}

Thus, the equivalent resistance of the new cable is R / 64.

4 0
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