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3 years ago

You accidentally drop a book down a stairwell. Assuming no air resistance,

Physics

2 answers:

Flauer [41]3 years ago

8 0

Answer:

7.4 rounding up - A p e x

Explanation:

Nimfa-mama [501]3 years ago

7 0

Answer:

if we drop it and not throw it then

after 0.75 how fast the book is falling is given by its velocity as

v= at

= 9.8 × 0.75

=7.35 m/s

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Consider the following statements. A. Heat flows from an object at higher temperature to an object at lower temperature; B. Heat

Monica [59]

Answer:

A. Heat flows from an object at higher temperature to an object at lower temperature

Explanation:

The option A obeys the 2nd law of thermodynamics. The heat will flow from the object at higher temperature to the object at Lower temperature till they reach an equilibrial state.

Heat doesn’t necessarily flow from an object with higher thermal energy to an object with lower thermal energy because an object has a higher thermal energy when it’s mass is more than the other. This makes B wrong.

C is wrong because heat moves from an object with higher temperature to objects with Lower temperature regardless of the state of matter.

8 0

3 years ago

Sunlight strikes a piece of crown glass at an angle of incidence of 38.0°. Calculate the difference in the angle of refraction b

zhuklara [117]

Answer:

Difference in the angle of refraction = 0.3°

41.04° is the minimum angle of incidence.

Explanation:

Angle of incidence = 38.0°

For yellow light :

Using Snell's law as:

$\frac {sin\theta_2}{sin\theta_1}=\frac {n_1}{n_2}$

Where,

Θ₁ is the angle of incidence

Θ₂ is the angle of refraction

n₁ is the refractive index for yellow light which is 1.523

n₂ is the refractive index of air which is 1

So,

$\frac {sin\theta_2}{sin{38.0}^0}=\frac {1.523}{1}$

${sin\theta_2}=0.9377$

Angle of refraction for yellow light = sin⁻¹ 0.9377 = 69.67°.

For green light :

Using Snell's law as:

$\frac {sin\theta_2}{sin\theta_1}=\frac {n_1}{n_2}$

Where,

Θ₁ is the angle of incidence

Θ₂ is the angle of refraction

n₁ is the refractive index for green light which is 1.526

n₂ is the refractive index of air which is 1

So,

$\frac {sin\theta_2}{sin{38.0}^0}=\frac {1.526}{1}$

${sin\theta_2}=0.9395$

Angle of refraction for green light = sin⁻¹ 0.9395 = 69.97°.

The difference in the angle of refraction = 69.97° - 69.67° = 0.3°

Calculation of the critical angle for the yellow light for the total internal reflection to occur :

The formula for the critical angle is:

${sin\theta_{critical}}=\frac {n_r}{n_i}$

Where,

${\theta_{critical}}$ is the critical angle

$n_r$ is the refractive index of the refractive medium.

$n_i$ is the refractive index of the incident medium.

n₁ is the refractive index for yellow light which is 1.523 (incident medium)

n₂ is the refractive index of air which is 1 (refractive medium)

Applying in the formula as:

${sin\theta_{critical}}=\frac {1}{1.523}$

The critical angle is = sin⁻¹ 0.6566 = 41.04°

5 0

4 years ago

Hello pleaseplease help meeeeeeeeee help me major points helpppp

Lana71 [14]

Question 1 is B: A long, wet season results in additional earthworms in a robin habitat

Question 2 is B.When a disease kills a large amount of the rabbit population

Question 3 is A: oxpeker bird ticks off the backs of zebras

Question 4 is D. Birds feed off the insects that are stirred up from the grasses as cattle move through.

Question 5 is D :Birds feed off the insects that are stirred up from the grasses as cattle move through

Hope this helps you!

8 0

3 years ago

Read 2 more answers

If you tried to use a diverging lens as a magnifier by placing the object at the focal point, what type of image would be produc

gladu [14]

Answer:

Upright and smaller than the object

Explanation:

Diverging lens as the name suggests that the rays diverge after the refraction and do not meet in reality. A concave lens is called diverging lens. When there is refraction of light through a concave lens then the light bends away from the principal axis and hence never meet in reality but on tracing the rays backwards the rays appear to meet leading to the formation of a virtual image, which is erect and smaller than the object for an object placed at the focus of the lens.

Similar image is formed for any case when the object is between optical center and infinity.

7 0

4 years ago

The coordinates of a bird flying in the xy plane are given by x(t)=αt and y(t)=3.0m−βt2, where α=2.4m/s and β=1.2m/s2. Calculate

yuradex [85]

The derivative of the function space as a function of time is equal to a function of speed as a function of time.

$x(t)=2.4t \\ \frac{x(t)}{t}=t \\ v_{x}(t)=t \\ \\ y(t)=3-1.2\times t^2 \\ \frac{y(t)}{t}=1.2\times2t \\ v_{y}(t)=2.4t$

The velocity vector is given by the vector sum of the velocities of both axes.

$v_{R}^2(t)=v_{x}^2(t)+v_{y}^2(t) \\ v_{R}^2(t)=(t)^2+(2.4t)^2 \\ \boxed {v_R(t)=2.6t}$

If you notice any mistake in my english, please let me know, because I am not native.

4 0

4 years ago

Read 2 more answers