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

Answers

Answer 1

Answer:

20 = 30 / t1

t1 = 3/2

40 = 30 / t2

t2 = 3/4

average speed = total distance / total time taken

= 30 + 30 / 3/2 + 3/4

= 60 /9/4

= 60 × 4/9

= 26.667


Related Questions

IM SOO CONFUSED PLS HELP!! The mass of the nucleus is approximately EQUAL to the mass number multiplied by ____ Atomic Mass unit.

a. 1
b. 10
c. 100
d. 1000​

Answers

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.

Which instrument changes kinetic energy into electrical energy?




electric motor

hair drier

electric bell

dynamo​

Answers

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.

identification of elements compounds and mixtures from a given table​

Answers

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

A long straight wire is parallel to one edge and is in the plane of a single-turn rectangular loop as shown. If the loop is moving in the plane shown so that the distance x changes at a constant rate of 20 cm/s, what is the magnitude of the emf induced in the loop at the instant x = 5.0 cm? Let / = 50 A, a = 50 cm, b = 6.0 cm.

Answers

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

A meter 0.0525 m from a wire measures a magnetic field of 7.14 x 10-6 T. How much current flows through the wire?​

Answers

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

id really appreciate it if you helped (I'll give you brainlist) ​

Answers

Explanation:

answer is in the picture above

Two uniform bars of the same dimensions are constructed from the same material. One bar has five evenly spaced holes through it and the second bar has only two holes. In these cases, the bars are slid over vertical pegs and rest on a horizontal surface, where friction between the bar and the surface is negligible. The two bars are each pulled by

horizontal forces of equal magnitude F from their right end as shown above. The bars' resulting angular accelerations are recorded.


Is the magnitude of the initial angular acceleration of the bar in case 1 larger than, smaller than or equal to the magnitude of the initial angular acceleration of the bar in Case 2? Explain your reasoning.

Answers

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.

Name the two types of vaporization and explain the difference between them. Give one example of each

Answers

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:

The Statue of Liberty is made of Copper that has turned on Says has WAGNE Bongo Wantse
said about this change?
The change is a physical change because the owner in the same is still there,
The change is a physical change beave a new chemical is was on the outside of the sale,
The change is not a physical change beans the plos at the stanje na dana),
The change is nga physical change because a new chemical istmes on the outside of the stalye

Answers

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.

Subject: science 41. A device used to stop flow of electric current A) open plug key B)Closed plug key C)Both A and B D) Rio start ​

Answers

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

Page
A car is moving at a rate of 72 km/ hr. How far
does the moves stop after 4 seconds

Answers

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

A person skateboards at 3.25 m/s for 55.0 s. How far did he travel?

Answers

178.75 m/s or 399.852 mph

a current of 12 A flows through a fan for 30 minutes.How many charge flows through then fan during this time?

Answers

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

what is the meaning of physics​

Answers

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.

A parallel network consist of three resistors 4 ohm, 8 ohm and 16 ohm .If the current in 8 ohm resistor is 3 A then what are the currents in other resistors

Answers

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

HELP, SCIENCE QUESTION I AM STUCK
6. Which of the following is NOT part of a circuit?
A. rim B. load C. power source D. conductor

Answers

The answer is A because it is not part of the circuit

When starting an exercise program, shrinking your goals down to realistic and attainable goals like just moving for 10 minutes a day, is better than setting a lofty goal of losing 10 pounds a week.

TRUE OR FALSE

Answers

Yes I agree with it. Explanation: Weight-loss goals can mean the difference between success and failure.J

Answer: True

Explanation:

Complete the equation to show the radioactive decay of carbon-14 to nitrogen-14

Answers

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.

What is measurement ?​

Answers

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

an object that is 15 cm tall is placed 44 cm in front of a diverging lens. A virtual image appears -14cm in front of the lens. determine the focal length of the lens .
SHOW YOUR WORK.
A) 0.09cm
B)-20.53cm
C)10.6cm
D)-0.04cm

Answers

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).


A 90kg football receiver named Reggie is running at 6.7m/s to catch a pass. A defensive back (103kg) named
Julio is waiting in position to hit him (standing still). They fall to the ground together after the tackle. How fast
are they going after the collision?

Answers

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.

Two particles, with identical positive charges and a separation of 2.65 10-2 m, are released from rest. Immediately after the release, particle 1 has an acceleration 1 whose magnitude is 5.00 103 m/s2, while particle 2 has an acceleration 2 whose magnitude is 7.70 103 m/s2. Particle 1 has a mass of 6.20 10-6 kg. (a) Find the charge on each particle. q1 = C q2 = C (b) Find the mass of particle 2. kg

Answers

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]

why trucks are made to have many tires?​

Answers

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:

the length of second hand of clock is 14cm, an ant sits on the top of second hand. find the following
i) speed of ant
ii) distance covered by ant in 150 seconds
iii) displacement in 150 seconds

Answers

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

please help me..im begging you​

Answers

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

Boyle's law: At constant temperature, the pressure of a gas is inversely proportional to volume.

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

Charles' law: At constant pressure, the volume of a gas is directly proportional to temperature. So,

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

Gay-Lussac's law: At constant volume, the pressure of a gas is directly proportional to temperature.

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

Avogadro's law: At same temperature and pressure, the volume of gas is directly proportional to moles of gas.

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

Combined gas law: When Boyle's law, Charles' law, and Gay-lussac's law are combined together then it is called combined gas law. So,

[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]

Graham's law of effusion: It states that the rate of effusion of a gas is inversely proportional to the square root of mass of its particles.

[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

In Part l, the independent variable was

Answers

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.

18. Magnesium is a silvery-grey metal. When heated in air it reacts with oxygen burning with a bright flame to form a white powder called magnesium oxide. From the paragraph identity a) TWO elements (2 marks)​

Answers

Answer:Magnesium and OXYGENNNN

Explanation:

Magnesium Oxide is still technically Magnesium

A circuit diagram with a power source labeled 12 V is connected to 3 resistors in series. The resistors are labeled 1.0 Ohms, 2.0 Ohms, and 3 Ohms. Calculate the equivalent resistance in the circuit shown.

0.55 Ω
1.8 Ω
2.0 Ω


Its A "0.55" I guessed and got it right

Answers

Answer:

there it is fella u were right with ur answer

who is the father of computer but not Charles Babbage can anyone guess​

Answers

Answer:

It's Obusively charles Babbage I guess

A cubic box has a 0.6 cubic decimetre side. Find the mass of air in the box in gram. (1 Liter of air has a mass of 1.3 g).

Answers

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.

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A study was done on the batting averages for two baseball players: Hitmore and Bunter. Data were collected over a period of time for baseball parks that are natural and artificial turf. It was found that Hitmore does better overall (.e., has a better batting average). However, for both natural and artificial turf separately, Bunter does better. Which of the following is correct? This is an example of a negative association between variables. This is an example of Simpson's Paradox. "Turf" is a lurking variable in this example Both (B) and (C) are correct This situation is mathematically impossible For a sixth-order Butterworth high pass filter with cutoff frequency 3 rad/s, compute the following:a. The locations of the poles. b. The transfer function H(s). c. The corresponding LCCDE description. i used to describe a food item having a spicy or salty quality without being sweet? In both poems, the connotation of the underlinedlanguage implies find the slope of the line passing through the points using the slope formula (5, 0), (2, 4) evaluate the given expression if w= 17, x= 29, and a =8 w+(1/x)+(1/z) a. 17.18 b.8.11 c. 94.13 d. 46.15 are you suprise that we generally have only two close friend why or why not Find the Value of x Toula has just baked a cake in the shape of a rectangle. Shewants to divide the cake into two right-angled triangles bycutting along a diagonal of the cake. Toula is then going to placea cake ribbon around the outside of each of the two triangularpieces of cake. If the length of the cake is 32 cm and its width is24 cm, how much cake ribbon will she need to buy, giving youranswer to an appropriate accuracy. When taken consistently, PrEP has been shown to reduce the risk of HIV infection in people who are at high risk bymore than___%.100%90%80%70% 10. Use the vertical line test to determine if the graph belowrepresents a function. If it is not a function, tell where thevertical line test fails. 11. If you put quotation marks around a key phrase in an internet search, what results will you get?A. Sites that contain all of those words in that orderB. Sites that contain none of those wordsC. Sites that contain all of those words in any orderD. Sites that contain any of those words 1. A nurse in a health clinic is reviewing contraceptive use with a group of adolescent clients. Which of the following statements by an adolescent reflects an understanding of the teaching? A."A water soluble lubricant should be used with condoms." B. "A diaphragm should be removed 2 hours after intercourse. 6. "Oral contraceptives can worsen a case of acne D. "A contraceptive patch is replaced once a month. Tanning Company analyzes its receivables to estimate bad debt expense. The accounts receivable balance is $360,000 and credit sales are $1,000,000. An aging of accounts receivable shows that approximately 5% of the outstanding receivables will be uncollectible. What adjusting entry will Tanning Company make if the Allowance for Doubtful Accounts has a credit balance of $1,200 before adjustment A square coffee shop has a perimeter of 20 meters. How long is each side of the coffee shop? Please help please just help me Othello Company understated its inventory by $20,000 at December 31, 2017. It did not correct the error in 2017 or 2018. As a result, Othello's stockholders' equity was: Question 4) Cmo______ (usted) a la escuela? a) vas b) voy d) va (a+b)^2*(a-b) please answer me fast Use the graph of the function to find its domain and range. Write the domain and range in interval notation.