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3 years ago

What is one measurement needed to calculate the speed of an object? Direction Mass Time Velocity

Physics

2 answers:

OlgaM077 [116]3 years ago

5 0

Answer:

time

Explanation:

Vlad [161]3 years ago

3 0

The answer is Time.

Formula: Distance/Time

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A car is travelling at a constant speed of 26.5 m/s. Its tires have a radius of 72 cm. If the car slows down at a constant rate

maksim [4K]

Answer:

Magnitude of angular acceleration = -3.95 rad/s²

Explanation:

Angular acceleration is the ratio of linear acceleration and radius.

That is

$\texttt{Angular acceleration}=\frac{\texttt{Linear acceleration}}{\texttt{Radius}}\\\\\alpha =\frac{a}{r}$

Radius = 72 cm = 0.72 m

Linear acceleration is rate of change of velocity.

$a=\frac{11.7-26.5}{5.2}=-2.85m/s^2$

Angular acceleration

$\alpha =\frac{a}{r}=\frac{-2.85}{0.72}=-3.95rad/s^2$

Angular acceleration = -3.95 rad/s²

Magnitude = 3.95 rad/s²

4 0

3 years ago

Describe a light wave and explain how light wave travel through solids liquids and gasses

marin [14]

Through refraction , it bends as it passes into a solid object

8 0

3 years ago

Select the correct answer. A credit union is a business that is owned by people who have something in common, offers you a place

Svetradugi [14.3K]

Answer:

The primary purpose in furthering their goal of service is to encourage members to save money. Another purpose is to offer loans to members. In fact, credit unions have traditionally made loans to people of ordinary means. YOU ARE PART OWNER. Credit unions are owned and controlled by the people, or members, who use their services. Your vote counts. A volunteer board of directors is elected by members to manage a credit union.

A credit union is a nonprofit financial cooperative owned by and operated for the benefit of its members. It accepts deposits, makes loans, and provides other services.

5 0

3 years ago

A 300 MHz electromagnetic wave in air (medium 1) is normally incident on the planar boundary of a lossless dielectric medium wit

Masja [62]

Answer:

Wavelength of the incident wave in air = 1 m

Wavelength of the incident wave in medium 2 = 0.33 m

Intrinsic impedance of media 1 = 377 ohms

Intrinsic impedance of media 2 = 125.68 ohms

Check the explanation section for a better understanding

Explanation:

a) Wavelength of the incident wave in air

The frequency of the electromagnetic wave in air, f = 300 MHz = 3 * 10⁸ Hz

Speed of light in air, c = 3 * 10⁸ Hz

Wavelength of the incident wave in air:

$\lambda_{air} = \frac{c}{f} \\\lambda_{air} = \frac{3 * 10^{8} }{3 * 10^{8}} \\\lambda_{air} = 1 m$

Wavelength of the incident wave in medium 2

The refractive index of air in the lossless dielectric medium:

$n = \sqrt{\epsilon_{r} } \\n = \sqrt{9 }\\n =3$

$\lambda_{2} = \frac{c}{nf}\\\lambda_{2} = \frac{3 * 10^{6} }{3 * 3 * 10^{6}}\\\lambda_{2} = 1/3\\\lambda_{2} = 0.33 m$

b) Intrinsic impedances of media 1 and media 2

The intrinsic impedance of media 1 is given as:

$n_1 = \sqrt{\frac{\mu_0}{\epsilon_{0} } }$

Permeability of free space, $\mu_{0} = 4 \pi * 10^{-7} H/m$

Permittivity for air, $\epsilon_{0} = 8.84 * 10^{-12} F/m$

$n_1 = \sqrt{\frac{4\pi * 10^{-7} }{8.84 * 10^{-12} } }$

$n_1 = 377 \Omega$

The intrinsic impedance of media 2 is given as:

$n_2 = \sqrt{\frac{\mu_r \mu_0}{\epsilon_r \epsilon_{0} } }$

Permeability of free space, $\mu_{0} = 4 \pi * 10^{-7} H/m$

Permittivity for air, $\epsilon_{0} = 8.84 * 10^{-12} F/m$

ϵr = 9

$n_2 = \sqrt{\frac{4\pi * 10^{-7} *1 }{8.84 * 10^{-12} *9 } }$

$n_2 = 125.68 \Omega$

c) The reflection coefficient,r and the transmission coefficient,t at the boundary.

Reflection coefficient, $r = \frac{n - n_{0} }{n + n_{0} }$

You didn't put the refractive index at the boundary in the question, you can substitute it into the formula above to find it.

$r = \frac{3 - n_{0} }{3 + n_{0} }$

Transmission coefficient at the boundary, t = r -1

d) The amplitude of the incident electric field is $E_{0} = 10 V/m$

Maximum amplitudes in the total field is given by:

$E = tE_{0}$ and $E = r E_{0}$

E = 10r, E = 10t

3 0

3 years ago

Please need help on this

ale4655 [162]

the answer is the third one down

7 0

3 years ago