Answer:
25 km/hr
Explanation:
Since Ali's average speed for his trip to school is u = 20 km/hr and his average speed for the return trip to back home from school is v = 30 km/hr, thus his total average speed for the journey is thus V = (initial average speed + final average speed)/2 = (u + v)/2
Substituting the values of the variables into the equation, we have
V = (u + v)/2
V = (20 km/hr + 30 km/hr)/2
V = 50 km/hr/2
V = 25 km/hr
So, the average speed for Ali's trip is 25 km/hr
Để có 100 lít nước ở 370C. Người ta pha nước đang sôi với nước ở 150C. Tính thể tích nước mỗi loại cần dùng.Biết khối lượng riêng của nước là 1000kg/m3
Answer:
nước sôi: 440/17 l
nước 15°C:1260/17 l
The mass of earth 6*10^24kg and radius is 400kg Now find the value of acceleration due to gravity when a object is 3600km from the earth surface
Answer:
Explanation:
the Earth is 6 xx 10^(24) kg and its radius is 6400 km. Find the acceleration due to gravity on the surface of the Earth. Updated On: 7-4-2021
when an apple falls towards the earth the earth moves up to meet the apple. Is it true? If yes, why is the earth motion not noticeable ?
Answer:
Explanation:
The apple also exerts an equal and opposite force on the earth but earth does not move because the mass of apple is very small,due to which the gravitational force produces a large acceleration in it (a=F/m) and we can see the apple falling towards the earth but the mass of earth is very large,the same gravitational .
How does modulus of elasticity change with the rise of temperature
Explanation:
With rise in temperature, the length of the material increases which decreases its stiffness. Thus, we can say that with rise in the temperature, the Young's modulus decreases.
where do we use friction in day to day life
Answer:
walking in ground
while playing carrom
"Measurement is essential in our life. Justify the statement.
Explanation:
Measurement plays an important role in our daily lives because they are useful to do basic tasks, such as taking the temperature of a child with the help of a thermometer,making time estimations,measure out medicines and find out weights, areas and volumes of different substances
Exercise b) 1) Fill in the blanks with the appropriate word: a) The pressure exerted by the air in atmosphere is called b) Pressure is the applied per unit area, c) The pressure ........as the depth of liquid increases. d) The SI unit of density is Az object fisats on water if the ...of the object is leva
Answer:
atmospheric pressure
b)
c)increases
d) ....
state the advantages and disadvantages of alkaline battery over a lead acid accumulator
Answer:
Alkaline batteries have longer shelf life than other batteries of the chloride type electrolyte batteries. They have a much higher energy density compared with other batteries. This allows the battery to produce the same energy while lasting longer than other batteries.
Advantage
1) Alkaline battery lasts long than other batteries
2) It have a much higher energy density
Disadvantage :
1) They are heavier and bulkier
2) They have high internal resistance
What is alkaline battery ?An alkaline battery is a type of primary battery that derives its energy from the reaction between zinc metal and manganese dioxide.
Advantage
Alkaline battery can produce same amount of energy by lasting longer than other batteries as it have longer shelf life than lead acid accumulator
Alkaline battery have a much higher energy density compared to lead acid accumulator
Disadvantage :
Alkaline battery are heavier and bulkier
Alkaline battery have high internal resistance
learn more about Alkaline battery
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Cho hai điện trở R1 = 12Ω và R2 = 18Ω được mắc nối tiếp nhau. Điện trở tương R12 của đoạn mạch có thể nhận giá trị nào trong các giá trị
Answer:
For two resistors R1 = 12Ω and R2 = 18Ω are connected in series. The equivalent resistance R12 of the circuit can take any of the values
a teacher drives from school to the mall. then she goes to the doctors office for a physical examination. what is the magnitude of her displacement
The magnitude of the teachers displacement is the difference between
the location of the school and the location of the doctors office
The reason behind the above expression are explained as follows
The known locations of the teacher;
Initial location; The school
Second location; The mall
The eventual location; The doctors office
The required information;
The magnitude of the teachers displacement
The method of obtaining the displacement of the teacher;
Qualitatively, the displacement of the teacher can be obtained by applying the definition of displacement as follows;
The definition of displacement is an object's change in position, given by the difference between its start and finish locations
According to the definition of displacement, therefore, the magnitude of
the teachers displacement is the distance between the school and the
doctors office which is given by the difference between the coordinates of
the location of the school and the location of the doctors office
The magnitude of the displacement of the teacher = The coordinate of the location of the doctors office - The coordinate of the location of the school
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What are the two groups of planets based on composition?
What are the phases of scientific method?
what is required for force to come into play
Answer:
An interaction of one object with another object results in a force between the two objects. Thus, at-least two objects must interact for a force to come into play.
express in standard form
(I)0.000038
Answer:
3.8 x 10^-5
Explanation:
all you doing is putting it in the standard form I hope this help
a loaf of bread has a mass of 2000g and a volume of 500 cm3. what is the density of the bread
Answer:
4g/cm^3
Explanation:
density = mass / volume
= 2000 / 500
= 4g/cm^3
Luis rushes 40m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60s.
What is Luis’s average speed over the 60s?
What is Luis average velocity over the 60s?
1. The average speed of Luis over the 60 s is 1.33 m/s
2. The average velocity of Luis over the 60 s is zero.
1. The average speed can be calculated with the following equation:
[tex] S = \frac{d}{t} [/tex]
Where:
d: is the total distance traveled
t: is the total time = 60 s
The total distance can be calculated by the sum of the distance traveled to the truck (40 m) and the distance traveled to his home (the same 40 m), as follows:
[tex] d = 40 m + 40 m = 80 m [/tex]
So, the average speed is:
[tex] S = \frac{d}{t} = \frac{80 m}{60 s} = 1.33 m/s [/tex]
Hence, Luis's average speed over the 60 s is 1.33 m/s.
2. Now, the average velocity is a vector given by:
[tex]v = \frac{\Delta x}{\Delta t} = \frac{x_{f} - x_{i}}{t}[/tex]
Where:
[tex]x_{f}[/tex]: is the final distance traveled (the way to his home) = 40 m
[tex]x_{i}[/tex]: is the initial distance traveled (the way to his truck) = 40 m
Δt: is the total time = t = 60 s
Given that Luis in his journey, returns to the same starting point (his house), the total displacement is zero, and so the average velocity is also zero:
[tex]v = \frac{x_{f} - x_{i}}{t} = \frac{40 m - 40 m}{60 s} = 0[/tex]
Therefore, Luis's average velocity over the 60 s is zero.
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As shown in the figure below, Luis rushes 40 m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60 s.
Answer:
What is Luis’s average velocity over the 60 s period?
Answer: 0 m/s
What is Luis’s average speed over the 60 s period?
Answer: 1.33 m/s
the slope of a line on a position vs time graph is the
a. velocity
b. time
c. distance
d. displacement
It's the velocity, but only the magnitude. It can't show the direction of the velocity. So it's better to call it speed.
What is Anatomy & Physiology in 5 words?
Answer:
Anatomy is the study of the structure and relationship between body parts.
Physiology is the study of the function of body parts and the body as a whole.
Explanation:
A carnot engine has an efficiency of 50% when its sink temperature is 27°C. The temperature of source is: a) 300°C b) 327°C c) 273°C d) 373°C
327 degrees
Have a great day!
whats the beginning of life called
Answer:
Abiogenesis in evolutionary science, not sure about creation science
Explanation:
Velocity may be positive,negative or zero.Explain this statement with diagram.
Answer:
/
Explanation:
1.What is laser?
2.List the uses of laser in everyday life
Laser means Light Amplication by Stimulated Emission of Radiation.
Uses of laser
DNA sequencing instrument
Cutting and welding materials
Semiconducting chip manufacturing
Military devices
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define electrical resistance in a metal conductor
Answer:
Resistance is defined as the property of a conductor to resist the flow of charges through it. The resistance of conductor is numerically given as the ratio of potential difference across its length to the current flowing through it.
Explanation:
Answer the following questions 1 What is the difference between mass and weight of an object. Will the mass and weight of an object on the earth be same as their values on Mars ? Why?
Answer:
difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.
What mechanism of energy is transferred by mass motion of fluid from one region of space to another?
Hai điện tích đặt cách nhau một khoảng R trong không khí thì lực tương tác
giữa chúng là 2.10−3N. Nếu khoảng cách đó mà đặt trong môi trường điện môi thì
lực tương tác giữa chúng là 10−3N. Để lực tương tác giữa hai điện tích đó khi đặt
trong môi trường điện môi bằng lực tương tác giữa hai điện tích đó khi đặt trong
không khí thì khoảng cách giữa 2 điện tích là bao nhiêu?
A skier is standing still on a flat area of snow.
The weight of the skier is 550 N. The total area of his skis in contact with the ground is 0.015
m2.
What is the pressure exerted on the ground by the skier?
3700 N / m2
37 000 N/m2
8.3 N/m2
0.83 N/m2
We know
[tex]\boxed{\sf Pressure=\dfrac{Force}{Area}}[/tex]
[tex]\\ \sf\longmapsto Pressure=\dfrac{550}{0.015}[/tex]
[tex]\\ \sf\longmapsto Pressure=36666Pa[/tex]
[tex]\\ \sf\longmapsto Pressure=36666N/m^2[/tex]
Most nearest value is 37000N/m^2
Hence option b is correct
is a corroding metal a physical or chemical change?
Answer:
Coording metal is a physical change.
A car travels 100 km to the east. If the first half of the distance is driven at 50 km/h and the second half at 100 km/h, what is the average velocity
First half:
50 km at 50 km/hr ... 1 hour
Second half:
50 km at 100 km/hr ... 1/2 hour
Total distance = 100 km
Total time = 1.5 hours
Average speed = (100 km) / (1.5 hrs)
Average speed = 66 and 2/3 km/hr
Average velocity = 66 and 2/3 km/hr East
The average velocity of the car would be 66.67 Kilometers / hours.
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object.
As given in the problem a car travels 100 km to the east. If the first half of the distance is driven at 50 km/h and the second half at 100 km/h,
The average velocity of the car = Total displacement / total time
=100 / 1.5
=66.67 Kilometers / hours
Thus, the average velocity of the car would be 66.67 Kilometers / hours.
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(1) A string of constant thickness and length I cm is stretched by a force of T Newton. A
tuning fork stamped 256 Hz sets the string vibrating at its fundamental frequency.
Find the frequency of the string when:
(i) Its length is doubled and the tension constant;
(ii) the tension is doubled and the length constant.
2) State the effect of increase in the tension on a wire on its frequency.
Answer:
Explanation:
i) frequency is the square root of the quotient of Tension over linear density/ all divided by two times the length.
linear density and tension are constant, so the numerator remains constant
The length is doubled, so the frequency is halved.
f = 128 Hz
ii) Doubling the tension increases the frequency by √2
f = 256√2 = 362 Hz
2) If other factors remain constant, increasing tension increases frequency.
