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3 years ago

A 2.73 kg cylindrical grinding wheel with a radius of 31 cm rotates at 1416 rpm. What is its angular momentum? Answers:

Physics

1 answer:

Nezavi [6.7K]3 years ago

5 0

Answer:

The angular momentum of the wheel is $19.45\ kg-m^2/s$ .

Explanation:

It is given that,

Mass of the wheel, m = 2.73 kg

Radius of the wheel, r = 31 cm = 0.31 m

Angular speed of the wheel, $\omega=1416\ rpm= 148.28\ rad/s$

We need to find its angular momentum. It is given by :

$L=I\omega$

I is the moment of inertia of the wheel, $I=\dfrac{mr^2}{2}$

$L=\dfrac{mr^2}{2}\times \omega$

$L=\dfrac{2.73\times (0.31)^2}{2}\times 148.28$

$L = 19.45\ kg-m^2/s$

So, the angular momentum of the wheel is $19.45\ kg-m^2/s$ . Hence, this is the required solution.

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Attempting to impress the skeptical patrol officer with your physics knowledge, you claim that you were traveling so fast that t

horsena [70]

Answer:

v_r = 1.268 × 10⁸ mi/hr

Explanation:

We are given;

wavelength of the red light; λr = 693 nm = 693 × 10^(-9) m

wavelength of the yellow light; λy = 582 nm = 582 × 10^(-9) m

Frequency is given by the formula;

f = v/λ

Where v is speed of light = 3 x 10^(8) m

Frequency of red light; f_o = [3 x 10^(8)]/(693 × 10^(-9)) = 4.33 x 10¹⁴ Hz

Similarly, Frequency of yellow light;

f = [3 x 10⁸]/(582 × 10^(-9)) = 5.15 x 10¹⁴ Hz

To find the speed of the car, we will use the formula;

f = f_o[(c + v_r)/c)]

Where c is speed of light and v_r is speed of car.

Making v_r the subject;

cf/f_o = c + v_r

v_r = c(f/f_o - 1)

So, plugging in the relevant values, we have;

v_r = 3 × 10⁸[((5.15 x 10¹⁴)/(4.33 x 10¹⁴)) - 1]

v_r = 3 × 10⁸(0.189)

v_r = 5.67 x 10⁷ m/s

Converting to mi/hr, 1 m/s = 2.23694 mile/hr

So, v_r = 5.67 × 10⁷ × 2.23694

v_r = 1.268 × 10⁸ mi/hr

5 0

4 years ago

Which of the following best describes a substance in which the temperature remains constant while at the same time it is experie

katen-ka-za [31]

Answer:

The right option is (d) substance undergoing a change of state

Explanation:

Latent Heat: Latent heat is the heat required to change the state of a substance without change in temperature. Latent heat is also known as hidden heat because the heat is not visible. The unit is Joules (J).

Latent heat is divided into two:

⇒ Latent Heat of fusion

⇒ Latent Heat of vaporization.

Latent Heat of fusion: This is the heat energy required to convert a substance from its solid form to its liquid form without change in temperature. E.g (Ice) When ice is heated, its temperature rise steadily until a certain temperature is reached when the solid begins to melts.

Latent Heat of vaporization: This is the heat required to change a liquid substance to vapor without a change in temperature. The latent heat depend on the mass of the liquid and the nature of the liquid. E.g When water is heated from a known temperature its boiling point (100°C) When more heat is supplied to its boiling temperature, it continue to boil without a change in temperature.

From The above, Latent heat brings about a change of state of a substance at a steady temperature.

The right option is (d) substance undergoing a change of state

4 0

3 years ago

A lamp has a current of 2.17 A. In hours, how long does it take for 1 mole of electrons to pass through the lamp?

Gennadij [26K]

<u>Answer:</u> The amount of time needed for 1 mole of electrons to pass through the lamp is 12.33 hrs.

<u>Explanation:</u>

We are given:

Moles of electron = 1 mole

According to mole concept:

1 mole of an atom contains $6.022\times 10^{23}$ number of particles.