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2 years ago

These four surfaces are opaque; that is they reflect or absorb certain rays of light determine the color

Physics

1 answer:

masya89 [10]2 years ago

4 0

In the first figure, the surface absorbs all colors except for green light, which is reflected: so, the surface will appear as green to our eyes, because green is the only color which is reflected by that surface.

Similarly, in the second figure, the surface absorbs all colors except for blue, and so the surface will appear blue to our eyes.

In the third figure, the surface absorbs all colors, so it will appear black to our eyes (because no colors are reflected, and black=absence of colors).

In the fourth figure, all colors are reflected: this means the surface will appear white to our eyes (white= sum of all colors).

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Imagine that the above hoop is a tire. the coefficient of static friction between rubber and concrete is typically at least 0.9.

Stels [109]

The hoop is attached.

Consider that the friction force is given by:
F = μ·N
 = μ·m·g·cosθ

We also know, considering the forces of the whole system, that:
F = -m·a + m·g·sinθ
and
a = (1/2)·g·sinθ

Therefore:
-(1/2)·m·g·sinθ + m·g·sinθ = μ·m·g·cosθ
(1/2)·m·g·sinθ = μ·m·g·cosθ
μ = (1/2)·m·g·sinθ / m·g·cosθ
 = (1/2)·tanθ

Now, solve for θ:
θ = tan⁻¹(2·μ)
 = tan⁻¹(2·0.9)
 = 61°

Therefore, the maximum angle you could ride down without worrying about skidding is 61°.

5 0

2 years ago

A 20kg mass approaches a spring at a speed of 30 m/s. The mass compresses the spring 12cm before coming to a stop. Calculate the

Oksana_A [137]

Answer:

625000 N/ m

Explanation:

m= 20 kg

v= 30 m/s

x= 12 cm

k = ?

Here when the mass when hits at spring its speed is

Vi= 30 m/s

Finally it comes to rest after compressing for 12 cm

i-e Vf = 0 m/s

Distance= S= 12 cm = 0.12 m

using

2aS= Vf2 - Vi2

==> 2a ×0.12 = o- 30 × 30

==> a = 900 ÷ 0.24 = 3750 m/sec2

Now we know;

F = ma

F= -Kx

==> ma= -kx

==> 20 × 3750 = -K × 0.12

==> k = 625000 N/ m

5 0

2 years ago

A mass of 630g is hung on a spring. Using Force = mass x gravity, what is the force of the mass, acting on the spring?

hodyreva [135]

Answer:

6.174N or roughly 6.2N

Explanation:

630g=0.63kg

F=m*g=0.63*9.8=6.174N

3 0

1 year ago

A square conducting loop 8.4 cm on a side is placed in a uniform B-field so that the plane of the loop is perpendicular to the d

arsen [322]

Answer:

Explanation:

area of square loop A = side²

= 8.4² x 10⁻⁴

A = 70.56 x 10⁻⁴ m²

when it is converted into rectangle , length = 14.7 , width = 2.1

area = length x width

= 14.7 x 2.1 x 10⁻⁴

= 30.87 x 10⁻⁴ m²

Let magnetic field be B

Change in flux = magnetic field x change in area

= B x ( 70.56 x 10⁻⁴ - 30.87 x 10⁻⁴ )

= 39.69 x 10⁻⁴ B

rate of change of flux = change in flux / time taken

= 39.69 x 10⁻⁴ B / 6.5 x 10⁻³

= 6.1 x 10⁻¹ B

emf induced = 6.1 x 10⁻¹ B

6.1 x 10⁻¹ B = 14.7 ( given )

B = 2.41 x 10

= 24.1 T

B ) magnetic flux is decreasing , so it needs to be increased as per Lenz's law . Hence current induced will be anticlockwise so that additional magnetic flux is induced out of the page.

4 0

2 years ago

Mars has two moons, Phobos and Deimos. Phobos orbits Mars at a distance of 9380 km from Mars's center, while Deimos orbits at 23

Sloan [31]

Answer:

The ratio is $\frac{T_1}{T_2} = 3.965$