A car travels first 30 km at a uniform speed of 20 km
/hr and went 30 km at a uniform speed of 40 km/hr
Find its average speed in km/hr

Answer:

Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events

Answer:

The comparison of an unknown quantity with a known quantity is called measurement

Answer:

physics is the study of functions, systems and and the explainable reasons why they do what they do.

Answer:

physics is the branch of science concerned with the nature and properties of matter and energy. it includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.

Answer:

The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable. ... The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable.

Evaporation and Boiling are the two vaporizations.

Evaporation is the type of vaporization that occurs at temperatures below the boiling point, whereas boiling is the type of vaporization that occurs at temperatures above the boiling point. The other type of vaporization is boiling, which occurs when a liquid is heated to the point where its vapor pressure equals the external pressure surrounding the liquid. When the liquid is heated, bubbles form within the liquid.

Hope this helps and if it does, don't be afraid to give my answer a "Thanks" and maybe a Brainliest if it's correct?  

Answer:

sample respond: Vaporization is the process by which a liquid becomes a gas. The two types of vaporization are evaporation and boiling. Evaporation takes place at the surface of a liquid, such as a puddle drying up. Boiling takes place below the surface of a liquid and causes bubbling, like a pot of water on a hot stove. Explanation:

Answer:

The mass of air in the box is 0.78 grams.

Explanation:

A litre equals a cubic decimetre. By definition of density ([tex]\rho[/tex]), in grams per litre, we calculate the mass of air inside the cube ([tex]m[/tex]), in grams:

[tex]m = \rho \cdot V[/tex] (1)

Where [tex]V[/tex] is the volume occupied by air within the cube, in litres.

If we know that [tex]V = 0.6\,L[/tex] and [tex]\rho = 1.3\,\frac{g}{L}[/tex], then the mass of air is:

[tex]m = \left(1.3\,\frac{g}{L} \right)\cdot (0.6\,L)[/tex]

[tex]m = 0.78\,g[/tex]

The mass of air in the box is 0.78 grams.

Answer:

a)  [tex]q=4.92*10^{-8} C[/tex]

b)  [tex]m=4.026*10^{-6} kg[/tex]

Explanation:

From the question we are told that:

Separation distance [tex]d=2.65*10^{-2} m[/tex]

Acceleration 1 [tex]a_1=5.00*10^3 m/s^2,[/tex]

Acceleration 2 [tex]a_2=7.70*10^3 m/s^2,[/tex]

Mass 1 [tex]m_1=6.20*10^{-6}[/tex]

Generally the equation for Force is mathematically given by

 [tex]F=ma[/tex]

For Particle 1

 [tex]F=6.2*10^{-6} *5*10^3[/tex]

 [tex]F=0.031 N[/tex]

Also

 [tex]F=\frac{kq_1*q2}{r^2}[/tex]

Where

 [tex]q_1=q_2[/tex]

Therefore

 [tex]0.031=\frac{9*10^9*q^2}{(2.65*10^-2)^2}[/tex]

 [tex]q=4.92*10^{-8} C[/tex]

b)

Generally the equation for Force is mathematically given by

 [tex]F=ma[/tex]

 [tex]0.031=7.7*10^3[/tex]

 [tex]m=4.026*10^{-6} kg[/tex]

Answer:

[tex]I=1.9A[/tex]

Explanation:

From the question we are told that:

Meter distance [tex]d=0.0525[/tex]

Magnetic field [tex]B=7.14*19^{-6}T[/tex]

Generally the equation for Magnetic field B is mathematically given by

 [tex]B =\frac{\mu *I }{2* \pi r}[/tex]

 [tex]7.14*19^{-6}T =\frac{ 1.26 *10^{-6} *I }{2* 3.142*0.0525}[/tex]

Where

Constant[tex]\mu=1.26 *10^{-6}[/tex]

 [tex]I=1.9A[/tex]

Therefore

The Current through the wire is

 [tex]I=1.9A[/tex]

Answer: 1.87

Explanation:

acellus

Answer:

The beta decay takes place.

Explanation:

The reaction of radioactivity of carbon 14 to nitrogen 14 is

There is a beta decay.  

The reaction is

[tex]C_{6}^{14}\rightarrow N_{7}^{14}+\beta _{-1}^{0}+ energy[/tex]

Here some energy is released in form of neutrino.

Complete Question:

The Statue of Liberty is made of copper that has turned green because it has undergone a change. What can be said about this change?

Group of answer choices.

A. The change is a physical change because the copper in the statue is still there.

B. The change is a physical change because a new chemical is formed on the outside of the statue.

C. The change is not a physical change because the color of the statue has changed.

D. The change is not a physical change because a new chemical is formed on the outside of the statue.

Answer:

D. The change is not a physical change because a new chemical is formed on the outside of the statue.

Explanation:

A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.

This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.

Additionally, a physical change is a type of change that involves an increase or decrease in the volume of a physical object (object). Also, this change can be reversed to the original state under certain conditions.

Since the Statue of Liberty which is made of copper turned green, the change is not a physical change because a new chemical is formed on the outside of the statue.

Solution :

The angular acceleration, [tex]$\alpha$[/tex] is obtained from the equation of the [tex]$\text{Newton's second law}$[/tex] of rotational motion,

Thus,

[tex]$\tau = F \times d$[/tex]

or [tex]$\tau = I \times \alpha$[/tex]

where [tex]$\tau$[/tex] is torque, F is force, d is moment arm distance, I is the moment of inertia

Thus, [tex]$\alpha=\frac{(F\times d)}{I}$[/tex]

Now if the force and the moment arm distance are constant, then the [tex]\text{angular acceleration is inversely proportional to the moment of inertia.}[/tex]

That is when, F = d = constant, then  [tex]$\alpha \propto \frac{1}{I}$[/tex] .

Thus, moment of inertia, I is proportional to mass of the bar.

The mass is less for the bar in case (1) in comparison with that with the bar in case (2) due to the holes that is made in the bar.

Therefore, the bar in case (1), has less moment of inertia and a greater angular acceleration.

Answer:

option a.

Explanation:

We can think of an atom as a nucleus (where the protons and neutrons are) and some electrons orbiting it.

We also know that the mass of an electron is a lot smaller than the mass of a proton or the mass of an electron.

So, if all the protons and electrons of an atom are in the nucleus, we know that most of the mass of an atom is in the nucleus of that atom.

Then we define the mass number, which is the total number of protons and neutrons in an atom. Such that the mass of a proton (or a neutron) is almost equal to 1u

Then if we define A as the total number of protons and neutrons, and each one of these weights about 1u

(where u = atomic mass unit)

Then the weight of the nucleus is about A times 1u, or:

A*1u = A atomic mass units.

Then the correct option is:

The mass of the nucleus is approximately EQUAL to the mass number multiplied by __1__ Atomic Mass unit.

option a.

Answer: The equations in column A is matched with gas laws in column B as follows:

21. PV = nRT : (g) Ideal gas law

22. [tex]V_{1}n_{2} = V_{2}n_{1}[/tex] : (f) Avogadro's law

23. [tex]P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex] : (e) Combined Gas Law

24. [tex]P_{1}T_{2} = P_{2}T_{1}[/tex] : (d) Gay-Lusaac's law

25. [tex]V_{1}T_{2} = V_{2}T_{1}[/tex] : (c) Charles' law

26. [tex]P_{1}V_{1} = P_{2}V_{2}[/tex] : (b) Boyle's law

27. [tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex] : (a) Graham's Law of effusion

Explanation:

(A) Ideal gas law: It states that the product of pressure and volume is directly proportional to the product of number of moles and temperature.

So, PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant

T = temperature

So, [tex]P_{1}V_{1} = P_{2}V_{2}[/tex]

[tex]V \propto T\\\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}\\V_{1}T_{2} = V_{2}T_{1}[/tex]

So,  [tex]P_{1}T_{2} = P_{2}T_{1}[/tex]

So, [tex]V_{1}n_{2} = V_{2}n_{1}[/tex]

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\or, P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex]

[tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex]

Thus, we can conclude that equation in column A is matched with gas laws in column B as follows:

21. PV = nRT : (g) Ideal gas law

22. [tex]V_{1}n_{2} = V_{2}n_{1}[/tex] : (f) Avogadro's law

23. [tex]P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex] : (e) Combined Gas Law

24. [tex]P_{1}T_{2} = P_{2}T_{1}[/tex] : (d) Gay-Lusaac's law

25. [tex]V_{1}T_{2} = V_{2}T_{1}[/tex] : (c) Charles' law

26. [tex]P_{1}V_{1} = P_{2}V_{2}[/tex] : (b) Boyle's law

27. [tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex] : (a) Graham's Law of effusion

Answer: reciever is going to be going the momentum which is 90 times 6.7, so defensive back who is 103 KG and standing still therefore has no momentum, so the collision is 6.7 m/s against the defense

Explanation:

zero momentum

newton's 1st law of motion, when something is acted upon by an unbalanced force.

Answer:

Dynamo

Explanation:

Dynamo started to rotate which is known as kinetic energy.When dynamo is in running it produces electricity.dynamo specially used for generating electricity.

Answer:

If the resistors are in parallel they must all experience the same voltage drop.

R * I = V

8 * 3 = 24 V    (if i is 3 amps)

24V / 4 ohm = 6 amps

24V / 16 ohm = 1.5 amps

Answer:

The magnitude of the emf induced in the loop is 2.4 × 10⁻⁵ V

Explanation:

The magnitude of the induced emf of a loop moving relative to a wire is given as follows;

The given parameters are;

I = 50 A, a = 50 cm, and b = 6.0 cm

The constant rate of change of x, v = 20 cm/s

Motional emf formula

The magnetic field due to the straight wire, B = μ₀·i/(2·π·x)

The flux given by the rectangular loop, Ф = BA =  μ₀·i/(2·π·x) × a × b

Therefore, we get;

[tex]e = \dfrac{-d\phi}{dt} = \dfrac{-\mu_0 \cdot i \cdot a\cdot b}{2 \cdot \pi} \times \dfrac{d}{dt} \left (\dfrac{1}{x} \right ) = \dfrac{-\mu_0 \cdot i \cdot a\cdot b}{2 \cdot \pi} \times \left (\dfrac{1}{x^2} \right ) \dfrac{dx}{dt}[/tex]

[tex]\because \dfrac{dx}{dt} = v[/tex]

Therefore;

[tex]e = \dfrac{-\mu_0 \cdot i \cdot a\cdot b}{2 \cdot \pi} \times \left (\dfrac{1}{x^2} \right ) \dfrac{dx}{dt} = \dfrac{-\mu_0 \cdot i \cdot a\cdot b}{2 \cdot \pi} \times \left (\dfrac{1}{x^2} \right ) \times v \left(\because \dfrac{dx}{dt} = v \right)[/tex]

μ₀ = 4·π × 10⁻⁷ H/m

We get;

[tex]e = \dfrac{4\cdot \pi \times 10^{-7} \, H/m\times50 \, A \times 0.5 \, m\times 0.06 \, m}{2 \cdot \pi} \times \left (\dfrac{1}{(0.05 \, m)^2} \right ) \times 0.2 \ m/s = 2.4 \times 10^{-5} \, V[/tex]

The induced emf, e = 2.4 × 10⁻⁵ V

Answer:

the elements are made up of only one kind of atom, the compounds consist of two or more elements that are chemically combined, and the mixtures are physical combination of two or more substances

Answer:

Q=21600C

Explanation:

Q=It.

Data

I=12A

t=30min

convert time from minutes to second

t=60*30

=1800s

Q=?

Q=It

=(12A)*(1800s)

Q=21600C

Answer:

Circuit Breaker - a protective device used to automatically blows and cuts the current when trouble in the circuit such as short circuit or overload occurs

Answer: Load carrying heavy vehicles have large number of wheels in order to reduce pressure on the contact patch on road. With large number of wheels, it becomes easy to distribute the entire pressure of loads in an even manner.

Explanation:

Answer: True

Explanation:

Answer:

Distance = 80 meters

Explanation:

Given the following data;

Speed = 72 km/hr

Time = 4 seconds

Conversion:

72 km/hr to meters per seconds = 72*1000/3600 = 72000/3600 = 20 m/s

To find the distance covered by the car;

Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.

Mathematically, speed is given by the formula;

[tex]Speed = \frac{distance}{time}[/tex]

Making distance the subject of formula, we have;

[tex] Distance = speed * time [/tex]

Substituting into the above formula, we have;

[tex] Distance = 20 * 4 [/tex]

Distance = 80 meters

Answer:

It's Obusively charles Babbage I guess

Answer:Magnesium and OXYGENNNN

Explanation:

Magnesium Oxide is still technically Magnesium

Answer:

there it is fella u were right with ur answer

Explanation:

answer is in the picture above

Answer:

The answer is below

Explanation:

i) Since the length of the second clock (radius) is 14 cm = 0.14 m, the distance covered by the second hand in one revelution is:

Distance covered = 2πr = 2π(0.14) = 0.88 m

The time taking to complete one revolution = 60 seconds, hence;

Speed = distance covered in one revolution / time take o complete a revolution

Speed = 0.88 m / 60 s = 0.0147 m/s

ii) Distance covered in 150 s = speed * 150 s = 0.0147 * 150 = 2.2 m

iii) Displacement in 150 seconds = distance from initial position to final position

At 150 s, the hand has covered 2 revolutions and moved 30 s. Hence:

Displacement in 150 seconds = speed * 30 s = 0.0147 * 30 = 0.44 m

Answer:

The correct option is (b).

Explanation:

Given that,

The height of the object, h = 15 cm

Object distance, u = -44 cm

Image distance, v = -14 cm

We need to find the focal length of the lens. Using the lens formula.

[tex]\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}\\\\\dfrac{1}{f}=\dfrac{1}{(-14)}-\dfrac{1}{(-44)}\\\\f=-20.53\ cm[/tex]

So, the focal length of the lens (-20.53 cm).