physics grade9 teacher guide​

Answer:

A. infrared

Explanation:

Heat lamps used to keep foods warm are infrared on the light spectrum

Answer:

F = -319.2 N

Explanation:

Given that,

The mass of a bicyclist, m = 70 kg

Mass of the bicycle = 9.8 kg

The speed of a bicycle, v = 16 m/s

We need to find the magnitude of the braking force of the bicycle come to rest in 4.0 m.

The braking force is given by :

[tex]F=ma\\\\=\dfrac{m(v-u)}{t}\\\\=\dfrac{(70+9.8)(0-16)}{4}\\\\=-319.2\ N[/tex]

So, the required force is 319.2 N.

Answer:

heavy molecules are pumped much more efficiently than light molecules. Most gases are heavy enough to be well pumped but it is difficult to pump hydrogen and helium efficiently.

Answer:

R ≈ 15 ohms

Explanation:

Using ohm's law equation,

I = V/R, to solve for the resistance of the heating coil.

R = V/I

Known:

V = 220 v = 220 kgm^2s^-3A^-1

I = 15 A

Unknown:

R =?

Solution:

R = (220 kgm^2s^-3A^-1)/ 15.0 A

R = 14.6 kgm^2s^-3A^-2

R ≈ 15 kgm^2s^-3A^-2

R ≈ 15 ohms

Answer: True

Explanation:

Government as an academic field of study refers to the study of political institutions, processes and theories taught in schools, colleges and higher institution of learning. It is called Political Science in higher institution.

Answer:

The 9th harmonic is 1,010.67 Hz.

Explanation:

Given;

length of the pipe, L = 1.23 m

speed of sound at 0°C = 331.5 m/s

A pipe closed at one end is known as a closed pipe;

The wavelength of the sound for the first harmonic is calculated as;

L = Node ------ > Antinode

[tex]L = \frac{\lambda }{4} \\\\\lambda = 4L[/tex]

First harmonic:  [tex]F_0 = \frac{V}{\lambda} = \frac{V}{4L}[/tex]

The wavelength of the sound for the first harmonic is calculated;

L = Node ----> Node + Node ------> Antinode

[tex]L = \frac{\lambda}{2} + \frac{\lambda}{4} = \frac{2\lambda+\lambda}{4} = \frac{3\lambda}{4} \\\\\lambda = \frac{4 L}{3}[/tex]

Second harmonic: [tex]F_1 = \frac{V}{\lambda} = \frac{3V}{4L}[/tex]

F₁ = 3F₀

The increment from F₀ to F₁ is 1 to 3; (odd number).

(1, 3, 5, 7, 9, 11, 13, 15, 17, 19..... n+2, where n is odd number)

The 9th harmonic = F₈

F₈ = 15F₀

[tex]F_8= 17(F_0) = 15 (\frac{V}{4L} )\\\\F_8 = 15(\frac{331.5}{4\times 1.23} )\\\\F_8 = 1,010.67 \ Hz[/tex]

Therefore, the 9th harmonic is 1,010.67 Hz.

The frequency of the 9th harmonic if the pipe is closed at one end is 605.48 Hz.

Based on the given information,

• The length (l) of the shortest pipe given is 1.23 m.

The speed of sound at 0 degree C is,

[tex]V = 331\sqrt{1+\frac{T}{273} } \\V = 331\sqrt{1+\frac{0}{273} } \\V = 331 m/s[/tex]

Now the condition is that the pipe is closed at one end. The formula to use in the given case is,

[tex]fn = \frac{nv}{4l} \\[/tex]

Here l is the length of the organ pipe.

Now the frequency of the 9th harmonic will be,

[tex]f9 = \frac{9v}{4l} \\\\f9 = \frac{9*331}{4*1.23} \\f9 = 605.48 Hz[/tex]

Thus, the frequency of the 9th harmonic if the pipe is closed at one end is 605.48 Hz.

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Answer:

In a way it does, but overall, there are many factors that affect your rank. In general, and talking about the average Platinum II, they are pretty decent according to casual player standards.

Explanation:

Answer:

Explanation:

From the given information:

Since both stars are in the same cluster, the magnitude and luminosity relationship can be calculated as:

[tex]m_1 - m_2 = -2.5 log _{10} (\dfrac{L_1}{L_2})[/tex]

Given that;

m_1 = 1 and

m_2 = 4

Therefore,

[tex]1 - 4 = -2.5 log _{10} ( \dfrac{L_1}{L_2})[/tex]

[tex]3 = -2.5 log _{10} ( \dfrac{L_1}{L_2})[/tex]

Making [tex]\dfrac{L_1}{L_2}[/tex] the subject of the formula:

[tex]\implies \dfrac{L_1}{L_2}= 10^{(\dfrac{3}{2.5})}[/tex]

=15.84

≅ 16

Hence, we can conclude that star X is more luminous by a factor of 16

The term used to describe the block of organs that are removed during the autopsy is Thoracic organs.

The organs that are removed during autopsy include:

The thoracic cavity contains organs and tissues that function in the respirator, cardiovascular, nervous and digestive system.

These thoracic organs include the following;

Thus, we can conclude that the term used to describe the block of organs that are removed during the autopsy is Thoracic organs.

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Answer:

B) It accelerated for 0.25s

Explanation:

Given the following data;

Acceleration = 20 m/s²

Final velocity, v = 5 m/s

Initial velocity, u = 0 m/s

To find the time, we would use the first equation of motion;

V = u + at

Substituting into the formula, we have;

5 = 0 + 20t

5 = 20t

Time, t = 5/20

Time, t = 0.25 seconds

Answer:

[tex]p =-1.03[/tex]

Explanation:

From the question we are told that:

Focal length of lens [tex]f=-0.304 m[/tex]

Image distance [tex]q=0.237 m[/tex]

Height of image [tex]H_i=0.343[/tex]  

Generally the lens equation is mathematically given by

[tex]\frac{1}{f} = \frac{1}{q} - \frac{1}{p}[/tex]

Where [tex]p[/tex] is Subject

[tex]p = \frac{(qf) }{(f - q)}[/tex]

[tex]p = \frac{(-0.237)(-0.304)) }{((-0.304) - (0.237))}[/tex]

[tex]p =-1.03[/tex]

Therefore the distance between  the person and the car is

[tex]p =-1.03[/tex]

Answer:

1.04 s

Explanation:

The computation is shown below:

As we know that

t = t' × 1 ÷ (√(1 - (v/c)^2)

here

v = 0.5c

t = 1.20 -s

So,

1.20 = t' × 1 ÷ (√(1 - (0.5/c)^2)

1.20 = t' × 1 ÷ (√(1 - (0.5)^2)

1.20 = t' ÷ √0.75

1.20 = t' ÷ 0.866

t' = 0.866 × 1.20

= 1.04 s

The above formula should be applied

Answer:

Earth has a much greater mass than objects on its surface

Answer:

300

Explanation:

the momentum is 300

p=mv

p=5×60

5×60 =300

Longitudinal waves

In a longitudinal wave the particles are displaced parallel to the direction the wave travels.

Answer:

Yes, I agree with rich

Explanation:

Yes I agree with rich.

Thus is because;

The electromagnetic process is what will determine how electromagnetic radiation will be emitted. Now, the mode of travel of electromagnetic energy is in the form of waves and then the wavelength of these waves is what will enable us know the form of energy. This includes light, x-rays, gamma rays e.t.c. This means that light and the others are just parts of the spectrum emitted and are called photons.

Thus, light can be said to be electromagnetic radiation.

I can agree with Rich that light is the same as electromagnetic radiation since the two terms can conveniently be used interchangeably.

Light has become a generic term that is used to describe all electromagnetic waves. All the waves in the electromagnetic spectrum have different frequencies and wavelengths but they are travel at the same speed which has been designated as "speed of light".

Therefore, i can agree with Rich that light is the same as electromagnetic radiation since the two terms can conveniently be used interchangeably.

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Answer:

Bacteria: Unicellular organisms that can cause disease in living things

Plant: A multicellular organism that makes it's own food

Animal: A multicellular organism that does not make it's own food

This is my alt account just grinding points

Answer:

Applications of zeroth law of thermodynamics:

1. When we get very hot food, we wait to make it normal. In this case, hot food exchanges heat with surrounding and brings equilibrium.

2. We keep things in the fridge and those things come equilibrium with fridge temperature.

3. Temperature measurement with a thermometer or another device.

4. In the HVAC system, sensors or thermostats are used to indicate temperature. It always comes in a thermal equilibrium with room temperature.

5. If you and the swimming pool you’re in are at the same temperature, no heat is flowing from you to it or from it to you (although the possibility is there). You’re in thermal equilibrium.

Answer:

No. Because it would correspond to zero Instantaneous acceleration.

Explanation:

hope this helps

Answer:

a. The system will rotate in the clockwise direction with a constant angular speed.

Explanation:

As all the clay is identical sphere and there will be hence same mass 'm' for all three clay spheres. Now their identical speed 'v' and collision time [tex]$'t_0'$[/tex] are also same. So all the spheres will exert same force F on the rod.

[tex]$f=\frac{mv}{t_0}$[/tex]

Force exerted by the clay Z on rod is passing through pivot, so no torque will be produced.

Now clay X will collide at near distance from pivot than that of clay Y.

So clay Y will produce more torque than clay X. So clay Y will give more clockwise torque. So rod will rotate clockwise.

Now in any impact because net force and net torque are zero (because in impact torque and force occurs in equal and opposite pairs). So net angular momentum will be conserved and hence angular speed will be constant.

Therefore it is clear that option (a) is correct.

Answer:

D)

The mass of the reactants is greater than the mass of the products.

Answer:

Explanation:

The classification will be made into 3 categories, which are

Ones that shortens wavelengths

Ones that lengthens wavelengths

Ones that has no effect on wavelengths

Shortens wavelengths -> Increase frequency

Lengthens wavelengths -> Decrease frequency

No effect -> Increase amplitude, decrease amplitude, increase damping, decrease damping.