A runner decreases his velocity from 20 m/s to 10 m/s in 2.0 s.
What was his average acceleration?

Answer:

0.67 m/s²

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 0 m/s

Final velocity (v) = 2 m/s

Time (t) = 3 secs

Acceleration (a) =?

Acceleration can be defined as the rate of change of velocity with time. It can be represented mathematically as:

Acceleration = change in velocity /time.

a = (v – u) /t

With the above formula, we can calculate the acceleration of the lift as shown below:

Initial velocity (u) = 0 m/s

Final velocity (v) = 2 m/s

Time (t) = 3 secs

Acceleration (a) =?

a = (v – u) /t

a = (2 – 0) /3

a = 2/3

a = 0.67 m/s²

Thus, the acceleration of the lift between 0 and A is 0.67 m/s².

Explanation:

p=mv

600kgms-1=m × 4ms-1

m=600kgms-1/4ms-1

m=150kg

The mass of the object which has momentum of 600kgm/s with the velocity of 4m/s is 150kg.

Momentum is the product of the mass and velocity of the object. Momentum is the quantity of motion which is made up of the amount of matter moved and the velocity at which it moves. Momentum is a vector quantity because it has both the magnitude and direction. The SI unit of momentum is kg.m/s (kilogram meter per second).

p = m × v

p = momentum of the object,

m = mass of the object,

v = velocity of the object

600kgm/s = m × 4m/s

m = 600/ 4

m = 150kg

Therefore, the mass of the object will be 150kg.

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Answer:

The time is 0.6 sec.

Explanation:

Given that,

Acceleration of car = 7.2 m/s²

Speed = 4 m/s

We need to calculate the time

Using equation of motion

[tex]v=u+at[/tex]

Where, u = initial velocity

v = final velocity

a = acceleration

t = time

Put the value in the equation

[tex]4=0+7.2\times t[/tex]

[tex]t=\dfrac{4}{7.2}[/tex]

[tex]t=0.6\ sec[/tex]

Hence, The time is 0.6 sec.

Answer:

balance, eyes, elbow in, follow-through

Explanation:

Answer:

because the leaf absorbs all the other colors except for green. So the leaf reflects the green color which is what we see. that is why a leaf spears to be green.

Explanation:

floor gang aooh sub to pewdiepie

Answer: A. Overweight and obesity

Explanation:

Overweight and obesity are labeled for ranges of weight that are greater than what is generally considered healthy for a given height. Hence, option A is correct.

Overweight and obesity are calculated by Body Mass Index (BMI). BMI is a person's weight in kilograms divided by the square of height in meters. The healthy adult human BMI ranges from 18.5 to 25.

If BMI is less than 18.5, it falls within the underweight range. If the BMI ranges from 25.0 to 29.9, it falls within the overweight range. If the BMI is greater than 30, it comes under the obesity range. A high BMI indicates high fatness.

Obesity and overweight are determined as an abnormal growth or excessive fat accumulation in the healthy range. It is caused by an energy imbalance between calories consumed and calories expended.

Obesity and Being overweight can cause certain diseases and health issues. It increases the risk of high blood pressure, heart disease, diabetes, and stroke.

It is important to maintain a healthy range BMI. Obesity and overweight are reduced by making the choice of healthier foods and regular physical activities like yoga and exercise.

Hence, The correct option is A) Overweight and Obesity.

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Answer:

S= ?

V=2m/sec

t=25s

S=V*t

S=2*25

S=50m

Answer:

1 and 2

Explanation:

If an object has constant acceleration, it's displacement at time t is:

Δx = v₀ t + ½ at²

For object 1:

0.44 = (0) (0.3) + ½ a (0.3)²

a = 9.78

3.14 = (0) (0.8) + ½ a (0.8)²

a = 9.81

So object 1's acceleration is approximately constant.

For object 2:

0.06 = (0) (0.3) + ½ a (0.3)²

a = 1.33

3.09 = (0) (2.1) + ½ a (2.1)²

a = 1.40

So object 2's acceleration is approximately constant.

For object 3:

0.44 = (0) (0.3) + ½ a (0.3)²

a = 9.78

3.09 = (0) (2.1) + ½ a (2.1)²

a = 1.40

So object 3's acceleration is not constant.

Answer:

The __law__ conservation

of state that either energy may produced nor destroyed

Answer:

d

Explanation:

When a teacher mixed zinc (Zn) with hydrogen chloride (HCl), one or more new substances formed. Hence, option (d) is correct.

A chemical reaction is a procedure that causes one group of chemical components to change chemically into another.

Chemical reactions, which can frequently be described by a chemical equation, traditionally include changes that only affect the locations of electrons in the formation and dissolution of chemical bonds between atoms, with no change to the nuclei (no change to the elements present).

The study of chemical processes involving unstable and radioactive elements, where both electronic and nuclear changes may take place, is known as nuclear chemistry.

When the teacher mixed zinc (Zn) with hydrogen chloride (HCl), chemical reaction happens and more than one new substances formed.

2Zn + 2HCl → 2ZnCl + H₂

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Answer:

s = 38.7 m

Explanation:

First we calculate the distance covered during uniform motion of reaction time.

s₁ = vt

where,

s₁ = distance covered during uniform motion = ?

v = uniform speed = 11 m/s

t = time = 2.3 s

Therefore,

s₁ = (11 m/s)(2.3 s)

s₁ = 25.3 m

Now, we calculate the distance covered during decelerated motion:

2as₂ = Vf² - Vi²

where,

a = deceleration = -4.5 m/s²

s₂ = distance covered during decelerated motion = ?

Vf = Final Velocity = 0 m/s

Vi = Initial Velocity = 11 m/s

Therefore,

2(-4.5 m/s²)s₂ = (0 m/s)² - (11 m/s)²

s₂ = (-121 m²/s²)/(-9 m/s²)

s₂ = 13.4 m

the total distance will be:

s = s₁ + s₂

s = 25.3 m + 13.4 m

s = 38.7 m

A micrometer is used to measure the diameter of a length of copper wire. The zero error and scale reading are as shown.The correct answer should be the micrometer.

The micrometer is an instrument that is capable of measuring the component of an object to very high precision. It is used to obtain accurate measurements in engineering.

In the case of the copper wire, the diameter of 0.3 mm was an approximation and a more accurate measure of the diameter would be obtained by using the micrometer.A micrometer is used to measure the diameter of a length of copper wire. The zero error and scale reading are as shown.The correct answer should be the micrometer.

Therefore, A micrometer is used to measure the diameter of a length of copper wire. The zero error and scale reading are as shown.The correct answer should be the micrometer.

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Answer:

159 ofc

Explanation:

Answer:

h = 10 cm

Explanation:

The magnification produced by a mirror is given by :

[tex]m=\dfrac{h'}{h}[/tex]

h' is the image size and h is the object size

We have, h = 10 cm, m = +1

So,

[tex]m=\dfrac{h'}{h}\\\\h=\dfrac{10}{1}\\\\h=10\ cm[/tex]

So, the size off the object is same as that of the size of the image i.e. 10 cm.

[tex]\huge\mathfrak\red {Answer:}[/tex]

If a train travelled 500 meters in 25 seconds then,

Speed = 500m/25sec

[tex]\mathfrak\purple {Hope\: this\: helps\: you...}[/tex]

speed=500m/25sec

20m/sec

Answer:

Option (D) : The object slows down.

Answer:

The barometer is supporting 75 cm of Hg due to atmospheric pressure.

Since the manometer is open to air pressure, the gas pressure is supporting the air pressure plus the 30 cm of Hg.

So the "absolute" gas pressure is 75 + 30 = 105 cm of Hg.

D.

They don't have directions.

The quantities with only magnitude and no direction are called scalar quantities. Therefore, option D is the correct answer.  

Scalar quantities have only magnitude but vector quantities have both magnitude and direction. Some examples of scalar quantities are,

• Mass

• Temperature  

• Speed

• Density

Thus, we conclude that the quantities with only magnitude and no direction are scalar quantities. Hence option D is the correct pair.

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Answer:

20

15

10

B

5

C

position (m)

0

D

-5

-10

-15

E

20

0 1 2 3

8

9

10

11

12

4 5 6 7

time (sec)

Explanation:

okk

Answer:

288 cm is 2.88 meters. This is because each centimeter is 1/100th of a meter, or in other words, each meter is 100 cm. To find out cm-m, divide the amount of cm by 100 and change the unit to m.

Explanation:

formula is cm/100=m

288/100= 2.88m

Answer:

What was not required by the Massachusetts Education law of 1642 is;

Children were to be sent to designated schoolmaster for their learning

Explanation:

The Law of 1642 required that parents and master see to it that their children knew the principles of religion and the capital laws of the commonwealth.

The important aspects of the 1642 Law includes;

1) The responsibility for the basic education and literacy of a child are those of the parents and masters of child apprentices

2) Reading and writing competency of all children and servants are a requirement

3) It is the duty of the government, where a parent or master are unable to meet their tutoring responsibility, to see that a child is placed where the basic educational requirement will be met.

The role of a schoolmaster or the setting of a formal school were yet to be formed as at that time.

Answer:

The correct answer is Children were to be sent to designated schoolmasters for their learning

The responsibility of educating children was on parents and apprenticeship masters, not on designated teachers or schoolmasters. However, the law did allow the government to step in if the supervising adults failed in their responsibilities.

Explanation:

Answer:

They vary quite a lot, yet there are some similarities

Explanation:

With Mercury, you have a hot and barren expanse of rock

With Venus, you also have a fairly hot and barren expanse of rock, with a molten core

With Earth, you have a warm/cool variant with water and a full atmosphere

With Mars, you have a colder and barren expanse of valleys and rock, with a rather paste-like ground

With Jupiter, we have our first gas giant, covered in clouds with a thick atmosphere

With Saturn, it is yet another gas giant, with rings of gas and rock and a dense core of metals, such as iron and nickel

With Uranus, it is also rather gas-full with a fair amount of water and methane, which results in its bluish color (an ice giant)

And finally with Neptune, it is the other ice giant, consisting of water, methane, and ammonia

So there are some similarities (gases, water, land formations, etc.) and some differences (rings, temperature, structure, etc.). Our planets are very unique to one another and continue to engage and surprise us.

Answer:

302129m

Explanation:

Using s= ut + 1/2at²

But u= 0

So

S= 1/2(3.1)(441.5)²

=302129m

Answer:49594.5

Explanation:

Answer:

A velocity is a vector unit, and average velocity can be described as the displacement divided by the time. The units for velocity can be understood from the definition to be meters/second or in common any distance unit over any time unit. The average speed of a body is described as the distance covered divided by the time elapsed.

Explanation:

the force of speed

Answer:

10 m/s

Explanation:

The average velocity is the slope of the graph.

m = (10 - 0)/(1 - 0)

m = 10/1

m = 10 m/s