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3 years ago

1) Classify each of the following as either a solid, liquid or gas at room temperature.

Physics

1 answer:

SVEN [57.7K]3 years ago

5 0

Answer:

air gas

diamond solid

copper solid

candle wax solid or melted would be liquid

Explanation:

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two cars are moving at constant speeds in a straight line along a major highway. The first is travelling at 20ms^-1 and the seco

Reika [66]

Answer:

$t=750s$

Explanation:

The two cars are under an uniform linear motion. So, the distance traveled by them is given by:

$\Delta x=vt\\x_f-x_0=vt\\x_f=x_0+vt$

$x_f$ is the same for both cars when the second one catches up with the first. If we take as reference point the initial position of the second car, we have:

$x_0_1=6km\\x_0_2=0$

We have $x_f_1=x_f_2$ . Thus, solving for t:

$x_0_1+v_1t=x_0_2+v_2t\\x_0_1=t(v_2-v_1)\\t=\frac{x_0_1}{v_2-v_1}\\t=\frac{6*10^3m}{28\frac{m}{s}-20\frac{m}{s}}\\t=750s$

8 0

2 years ago

A 221 g cart starts from rest and rolls in the right direction (positive) down an incline. The incline is at a height of 5 cm. A

Julli [10]

Answer:

1) p₀ = 0.219 kg m / s, p = 0, 2) Δp = -0.219 kg m / s, 3) 100%

Explanation:

For the first part, which is speed just before the crash, we can use energy conservation

Initial. Highest point

Em₀ = U = mg y

Final. Low point just before the crash

Emf = K = ½ m v²

Em₀ = Emf

m g y = ½ m v²

v = √ 2 g y

Let's calculate

v = √ (2 9.8 0.05)

v = 0.99 m / s

1) the moment before the crash is

p₀ = m v

p₀ = 0.221 0.99

p₀ = 0.219 kg m / s

After the collision, the car's speed is zero, so its moment is zero.

p = 0

2) change of momentum

Δp = p - p₀

Δp = 0- 0.219

Δp = -0.219 kg m / s

3) the reason is

Δp / p = 1

In percentage form it is 100%

3 0

3 years ago

4. Many of the teachers think that if a student sleeps more on the night before the test, then they

Effectus [21]

Answer:

a sleep doesnt get to depict whether you get a good grade or not its what you know.

8 0

10 months ago

The maximum wavelength an electromagnetic wave can have and still eject an electron from a copper surface is 264 nm .What is the

Tamiku [17]

Answer:

4.71 eV

Explanation:

For an electromagnetic wave with wavelength

$\lambda=264 nm = 2.64\cdot 10^{-7} m$

the energy of the photons in the wave is given by

$E=\frac{hc}{\lambda}=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{2.64\cdot 10^{-7}m}=7.53\cdot 10^{-19} J$

where h is the Planck constant and c the speed of light. Therefore, this is the minimum energy that a photon should have in order to extract a photoelectron from the copper surface.

The work function of a metal is the minimum energy required by the incident light in order to extract photoelectrons from the metal's surface. Therefore, the work function corresponds to the energy we found previously. By converting it into electronvolts, we find:

$E=\frac{7.53\cdot 10^{-19} J}{1.6\cdot 10^{-19} J/eV}=4.71 eV$

3 0

2 years ago

2. Lenses such as those in microscopes and telescopes depend on which property of<br><br> light?

Marizza181 [45]

Answer:

The eyepiece comprises a converging lens that is a magnifying lens. The lens has a short focal length,

This lens magnifies this image.

Explanation:

In lenses such as those in microscopes and telescopes, the objective forms an image with the following features:

1. Image is real

2. Image is diminished in size

3. Also, the image formed is upside-down.

The eyepiece comprises a converging lens that is a magnifying lens. The lens has a short focal length,

This lens magnifies this image.

5 0

2 years ago