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Thepotemich [5.8K]
2 years ago
6

what is the speed of a 2.5-kilogram mass after ot has fallen freely from rest through a distance of 12 meters? a) 4.8 m/s b) 15

m/s c) 30. m/s d) 43 m/s
Physics
2 answers:
larisa [96]2 years ago
6 0
Vf^2 = Vi^2 + 2ad
Vf^ = 0 + 2(-9.8)(-12)
Vf^2 = 235.2
Vf = 15.3 m/s 

The correct answer is b) 15 m/s 
Otrada [13]2 years ago
6 0

v₀ = initial velocity of the mass = 0 m/s                (since the mass falls from rest)

a = acceleration = acceleration due to gravity = 9.8 m/s²

d = vertical distance traveled = 12 m

v = final velocity of the mass

Using the kinematics equation

v² = v₀² + 2 a d

v² = 0² + 2 (9.8) (12)

v² = 235.2

v = √235.2

v = 15 m/s

hence the speed of mass comes out to be

b) 15 m/s

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A pendulum is made of a small sphere of mass 0.250 kg attached to a lightweight string 1.20 m in length. As the pendulum swings
forsale [732]

Answer:v=2 m/s

Explanation:

Given

Length of string L=1.2 m

mass of pendulum m=0.25 kg

maximum inclination with vertical \theta =34

vertical Rise of Pendulum from its mean position  is given by

\Delta h=L(1-\cos \theta )

Conserving Energy at top and bottom point

Potential Energy of sphere is converted into kinetic energy of sphere

mgL(1-\cos \theta )=\frac{mv^2}{2}

v=\sqrt{2gL(1-\cos \theta )}

v=\sqrt{2\times 9.8\times 1.2(1-\cos 34)}

v=\sqrt{4.021}

v=2 m/s

5 0
2 years ago
A flashlight beam makes an angle of 60 degrees with the surface of the water before it enters the water. in the water what angle
alexira [117]
<h3><u>Answer</u>;</h3>

= 22°

<h3><u>Explanation</u>;</h3>
  • According to Snell's law, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. The constant value is called the refractive index of the second medium with respect to the first.
  • Therefore; Sin i/Sin r = η

In this case; Angle of incidence = 90° -60° =30°, angle of refraction =? and η = 1.33

Thus;

Sin 30 / Sin r = 1.33

Sin r = Sin 30°/1.33

       = 0.3759

r = Sin^-1 0.3759

   = 22.08

   <u>≈ 22°</u>

3 0
2 years ago
Now consider θc, the angle at which the blue refracted ray hits the bottom surface of the diamond. If θc is larger than the crit
Dennis_Churaev [7]

Complete Question:

A beam of white light is incident on the surface of a diamond at an angle \theta_{a},  since the index of refraction depends on the light's wavelength, the different colors that comprise white light will spread out as they pass through the diamond. For example, the indices of refraction in diamond are n_{red} = 2.410 for red light and n_{blue} = 2.450 for blue light. Thus, blue light and red light are refracted at different angles inside the diamond. The surrounding air has n_{air} = 1.000.

Now consider θc, the angle at which the blue refracted ray hits the bottom surface of the diamond. If θc is larger than the critical angle θcrit, the light will not be refracted out into the air, but instead it will be totally internally reflected back into the diamond. Find θcrit. Express your answer in degrees to four significant figures.

Answer:

\theta_{crit} = 24.09^{0}

Explanation:

Only the blue refracted ray is related to the critical angle in this question

n_{air} = 1.000

n_{blue} = 2.450

The relationship between the critical angle(\theta_{crit}), n_{air} and n_{blue} can be given as sin \theta_{crit} = \frac{n_{air} }{n_{blue} }

sin \theta_{crit} = \frac{1 }{2.450 }\\\theta_{crit} = sin^{-1} \frac{1 }{2.450 }\\\theta_{crit} = sin^{-1} 0.4082^{0}\\  \theta_{crit} = 24.09^{0}

6 0
2 years ago
At the normal boiling temperature of iron, TB = 3330 K, the rate of change of the vapor pressure of liquid iron with temperature
Margaret [11]

The molar latent enthalpy of boiling of iron at 3330 K is  ΔH = 342 \times 10^3 J.

<u>Explanation:</u>

Molar enthalpy of fusion is the amount of energy needed to change one mole of a substance from the solid phase to the liquid phase at constant temperature and pressure.

                      d ln p = (ΔH / RT^2) dt

                   (1/p) dp = (ΔH / RT^2) dt

                    dp / dt = p (ΔH / RT^2) = 3.72 \times 10^-3

                  (p) (ΔH) / (8.31) (3330)^2 = 3.72 \times 10^-3

                          ΔH = 342 \times 10^3 J.

8 0
2 years ago
Read 2 more answers
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Greeley [361]

Answer:

Explanation:

position of centre of mass of door from surface of water

= 10 + 1.1 / 2

= 10.55 m

Pressure on centre of mass

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10 ⁵ + hdg

= 10⁵ + 10.55 x 1000 x 9.8

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= pressure at the centre x area of the door

= .9 x 1.1 x 2.0339 x 10⁵

= 2.01356 x 10⁵ N

pressure centre will be at 10.55 m below the surface.

When the car is filled with air or  it is filled with water , in both the cases pressure centre will lie at the centre of the car .

7 0
2 years ago
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