A body starts with a velocity of 20 m/s, accelerates uniformly for a time t, moves with constant velocity for the same time, and finally decelerates to rest, again taking a time t. Given that the final deceleration is three times the original acceleration, and the total distance travelled is 140 m, find t.

Answers

Answer 1

Answer:

t=0.14s

Explanation:

t=[tex] \frac{s}{v} [/tex]t=[tex] \frac{20}{140} [/tex]Where s= speedV=distance And t=time

Related Questions

A car traveling at 30 m/s is brought to rest at a constant rate in 20 s by applying the brake. a) What is its acceleration? b) How far did it travel after the brake was applied?

Answers

acceleration = -30/20 = -1.5 m.s^2
V^2 = U ^2 + 2 a s
0 = 900 - 2 x 1.5 x s
3 s = 900
s = 300 m

Will give brainliest!!!!! Help asap

Answers

Answer:

Correct choice: 5,400 Km/h

Explanation:

Unit Conversions

We'll use the following conversions:

1 Km = 1,000 m

1 h = 3,600 s

Convert the speed of sound in water (1.5\cdot 10^3\ m/s) to Km/h:

[tex]\displaystyle 1.5\cdot 10^3\ m/s*\frac{ 3,600\ s/h}{ 1000 \ Km/m}[/tex]

[tex]=5,400\ Km/h[/tex]

Correct choice: 5,400 Km/h

is 4x a term? or does it have to remove the 4 to be a term

Answers

Answer:

4x is a term oonly

No need to be romoved

Tension force ........... throughout a string that changes direction over a pulley.
(Fill in the blank)

Answers

Answer:

"is constant"

An object is traveling with a velocity of 3.05 m/s. The object then accelerates at 2.82 m/s-over a
displacement of 18.4 m. What is its final velocity?

Answers

Answer:

Final velocity (v) = 5.148 m/s (Approx)

Explanation:

Given:

Initial velocity (u) = 3.05 m/s

Acceleration (a) = 2.82 m/s²

Displacement (s) = 18.4 m

Find:

Final velocity (v)

Computation:

v² = u² + 2as

v² = (3.05)² + 2(2.82)(3.05)

v² = 9.3025 + 17.202

v² = 26.5045

v = 5.148 m/s (Approx)

Do 2. A cyclist starts from rest and accelerates along a straight path to a speed of
12.15 m/s in a time of 4.5 seconds.
What is the cyclist's acceleration to the nearest tenth?
O
54.7 m/s2
o
24.3 m/s?
2.7 m/s2
De
3.4 m/s?

Answers

The cyclist's acceleration to the nearest tenth is: C. 2.7 [tex]m/s^2[/tex].

Given the following data:

Initial velocity = 0 m/s (since the cyclist starts from rest).Final velocity = 12.5 m/s.Time = 4.5 seconds.

To find the cyclist's acceleration to the nearest tenth:

Acceleration is calculated by subtracting the initial velocity from the final velocity and dividing by the time.

Mathematically, acceleration is given by the formula;

[tex]A = \frac{V - U}{t}[/tex]

Where:

A is the acceleration.V is the final velocity.U is the initial velocity.t is the time measured in seconds.

Substituting the given parameters into the formula, we have;

[tex]A = \frac{12.5\; - \;0}{4.5} \\\\A = \frac{12.5}{4.5}[/tex]

Acceleration, A = 2.7  [tex]m/s^2[/tex]

Therefore, the cyclist's acceleration to the nearest tenth is 2.7 [tex]m/s^2[/tex].

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How much is the weight of a 1 kg mass at the pole and the equator of the earth

Answers

Given parameters:

Mass given  = 1kg

Unknown:

Weight of the body at pole and equator = ?

Solution:

Both locations are on the surface of the earth. Generally, we take 9.8m/s² as the acceleration due to gravity on the earth.  

       Weight  = mass x acceleration due to gravity

But little disparity occurs in the value of acceleration due to gravity from the pole to equator. This is due to equatorial bulge.

   At the equator  , 9.780 m/s²

               pole  9.832 m/s²

Weight at equator = 1 x 9.780  = 9.78N

Weight at the pole = 1  x 9.832 = 9.832N  

A .25 kilogram baseball is thrown upwards with a speed of 30 meters per second. Neglecting friction the maximum height reached by the baseball is approximately

Answers

Answer: 46 meters

Explanation:

The maximum height reached by the base ball is 45.9 meters.

To find the maximum height the given values are,

Mass = 25 Kg

speed v = 30 meters per second.

What is the height of baseball reached?

As the ball goes up, it acts due to the gravity.

The gravity slows an upward-moving object,

Acceleration due to gravity = 9.8 m/s every second,

the baseball reaches its greatest height in (30/9.8) = 3.06 seconds.

At that instant, its speed is zero.

The baseball's average speed from toss to peak is

            (1/2) (30 + 0)  =  15 m/s .

The baseball average speed = 15 m/s

And the time for greatest height = 3.06 seconds.

Substituting the given values,

The ball rises can be calculated as

 (15 x 3.06)  =  45.9 meters.

Thus, the baseball reached the maximum height approximately is 45.9 meters.

Learn more about the height due to gravity,

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PLEASE HELP
Question 4 of 10
Which statement is true of a piece of ice at 0°C that is put into a freezer at
-18°C?
A. The ice cube will remain unchanged.
B. The ice cube will gain mass from the surroundings.
C. The ice cube will lose thermal energy to the surroundings.
D. The ice cube will gain thermal energy from the surroundings.

Answers

The ice cube will lose thermal energy to the surroundings. The given statement is true of a piece of ice at 0°C that is put into a freezer at -18°C. Thus, the correct option is C.

What is thermal energy?

The term thermal energy is used loosely in various different contexts in physics and engineering mainly. Thermal energy can refer to several different well-defined physical concepts. These concepts include the internal energy or the enthalpy of a body of matter and the radiation energy, the heat energy, which is defined as a type of energy transfer and it is the characteristic energy of a degree of freedom.

If a piece of ice at 0°C that is put into a freezer at -18°C then it can be said that the ice cube will lose thermal energy to the surroundings.

Therefore, the correct option is C.

Learn more about Thermal energy here:

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3. A substance has a density of 19.3 g/ml. What is the volume of 20.2 g of the
substance? Hint: density can be used as a conversions factor

Answers

Answer:

The answer is 1.05 mL

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\ [/tex]

From the question we have

[tex]volume = \frac{20.2}{19.3} \\ = 1.04663212...[/tex]

We have the final answer as

1.05 mL

Hope this helps you

In positron-emission tomography (PET) used in medical research and diagnosis, compounds containing unstable nuclei that emit positrons are introduced into the brain, destined for a site of interest in the brain. When a positron is emitted, it goes only a short distance before coming nearly to rest. It forms a bound state with an electron, called "positronium", which is rather similar to a hydrogen atom. The binding energy of positronium is very small compared to the rest energy of an electron. After a short time the positron and electron annihilate. In the annihilation, the positron and the electron disappear, and all of their rest energy goes into two photons (particles of light) which have zero mass; all their energy is kinetic energy. These high energy photons, called "gamma rays", are emitted at nearly 180° to each other. What energy of gamma ray (in MeV, million electron volts) should each of the detectors be made sensitive to? (The mass of an electron or positron is 9 × 10-31 kg. 1 eV = 1.6 × 10-19 joules.

Answers

Answer:

Energy of gamma ray = 506250 eV

Explanation:

We are told that the mass of an electron or positron is 9 × 10-31 kg.

This means that their energies will be the same.

Thus; E_e = E_p

Now, since electron and positron annihilate to form gamma(γ) particle, then using work energy principle, we have;

E_γ + E_γ = E_e + E_p

Thus;

2E_γ = E_e + E_p

Since E_e = E_p, we now have;

2E_γ = 2E_e

Thus;

E_γ = E_e

Since all the energy of the electron is converted, then from Einstein's relativity theory, this implies that;

E_e = mc²

c is speed of light = 3 × 10^(8) m/s

And m is given as 9 × 10^(-31) kg

Thus;

E_e = 9 × 10^(-31) × (3 × 10^(8))^(2)

E_e = 810 × 10^(-16) J

Since E_γ = E_e

Thus;

E_γ = 810 × 10^(-16) J

We are given that; 1.6 × 10^(-19) J = 1eV

Thus; 810 × 10^(-16) J gives;

(810 × 10^(-16) × 1)/(1.6 × 10^(-19)) = 506250 eV

I WILL MARK YOU AS BRAINLIEST IF RIGHT
In order to climb up a mountainside, a train needs to start at a speed of 40 mph. The speed limit on the track, however, is 25 mph. How much time does the train need to get up to 40 mph if it can accelerate 4 mph per minute ?

Answers

Let's see what to do buddy.....

_________________________________

[tex]Acceleration = 4 \: \: \frac{mile}{ h } p( min ) [/tex]

Thus ;

The speed increases 4 units per minute.

The train has a speed of 25 mph now.

After a minute it has a speed of 29 mph.

After a minute it has a speed of 33 mph.

After a minute it has a speed of 37 mph.

Look ; 4 units per minute means 4 units per 60 seconds, thus the speed increases 1 unit per 15 seconds .

If the speed wants to increasing from 37 to 40 , needs 3 × 15 seconds = 45 sec.

So we have : 1 min + 1 min + 1 min + 45 sec .

3 minutes and 45 seconds or 225 seconds need to the speed increasing from 25 mph to 40 mph.

_________________________________

And we're done.....♥️♥️♥️♥️♥️

5
2. When you keep the mass the same and decrease the unbalanced force how does the acceleration change?

Answers

Answer:

The acceleration will decrease due to less force acting on the object.

Explanation:

Sedimentary rock turns into magnum through which process

Answers

Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. This sediment is often formed when weathering and erosion break down a rock into loose material in a source area.

Two cars traveling in the same direction pass you at exactly the same time . The car that is going faster

Answers

moves farther in the same amount of time.

Explanation:

based on my answer......

we supposed to assume that both cars are equal except for speed. So they would have the same mass.....

Anyway, the question doesn't tell you anything about weight or size, so you can't tell from the information given which has more mass.

But the very definition of 'faster' is 'moves farther in the same amount of time'.

Hope this helps

Answer:

They both moves at the same speed

Explanation:

hope it works

A chemical symbol is to an element as a chemical formula is to a(n)

Answers

A subscript is the answer

Can air be forced into a smaller space? Explain with an example.
I will give out brainliest to person who has best answer☺️

Answers

Answer:

Yes. Yes, you can.

Explanation:

Combinations of increased pressure and decreased temperature force gases into containers that we use every day. You might have compressed air in a spray bottle or feel the carbon dioxide rush out of a can of soda. Those are both examples of gas forced into a smaller space at a greater pressure.

Hope this helps :)

A motorcycle is stopped at a stop light. When the light turns green it
accelerates at 4.2 m/s^2. How far does it travel during 3 s? *

Answers

Answer: 18.9 m

Explanation:

i did the kinematic equation & found the answer.

We can compare these two interactions on the basis of impulse (see above), but sometimes, we are more interested in the forces (human body can withstand very large amount of impulse, if it's delivered over a long time with small forces, but we cannot withstand very large forces lasting over more than a few milliseconds, delivering relatively small impulse). In order to estimate average force from impulse, we need the duration of interaction. Suppose that the contact of the bat with the baseball in (b) lasts for 0.7 milliseconds. What is the magnitude of the average force that the bat exerts on the baseball, for the duration of contact

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

 [tex]I =  476 \ N \cdot s [/tex]

b

 [tex]I_1 =  14.21 \  N\cdot s [/tex]

c

    [tex]F  = 20300 \  N [/tex]

Explanation:

Considering the first question

From the question we are told that

   The force produced is [tex]F  =  3400 \ N[/tex]

   The duration of the punch is  [tex]t =  0.14 \  s[/tex]

Generally the impulse delivered is mathematically represented as

    [tex]I =  F  *  t[/tex]

=>    [tex]I =  3400  *  0.14[/tex]

=>    [tex]I =  476 \ N \cdot s [/tex]

Considering the second  question

   The approaching velocity of the ball is  [tex]v_b  =  45 \ m/s[/tex]

    The leaving  velocity of the ball is  [tex]v_l  =  -53 \ m/s[/tex]

     The mass of the ball is  [tex]m_b  =  0.145 \  kg[/tex]

Generally the magnitude of the impulse delivered is mathematically represented as

     [tex]I_1 =  m*  v_b  - m *  v_l[/tex]

=>     [tex]I_1 =  [0.145 *  45]  - [0.145 * -53][/tex]

=>     [tex]I_1 =  14.21 \  N\cdot s [/tex]

Considering the third  question

     The  duration of the impact of the bat is  [tex]t _1 =  0.7 \ ms  =  0.7 *10^{-3} \  s[/tex]

      Generally the average force exerted by the bat is mathematically represented as  

       [tex]F  =  \frac{I_1}{t_1}[/tex]

=>     [tex]F  =  \frac{14.21 }{0.7 *10^{-3}}[/tex]

=>       [tex]F  = 20300 \  N [/tex]

 

Oil is a powerful source of energy used for cars, machines, and many other purposes. While studying sources of energy that could replace the use of oil, a student thinks about solar power, wind power, nuclear power, and electric batteries. The students asks, "Which type of source will waste the least energy and provide the most energy in all situations?" Which best describes why a scientist would ask a different question than this one?

The question asks about subjective personal preferences regarding energy.

The question focuses on the objective measurements of amounts of energy.

The question has too wide of a focus, as though all situations can be studied at once.

The question is focused on the future and finding new answers about changing needs.

Answers

Answer:

The question has too wide of a focus, as though all situations can be studied at once

Explanation:

I took the test

Answer:

The question has too wide of a focus, as though all situations can be studied at once

Explanation:

i took ed test

On the surface of the earth the weight of an object is 200 lb. Determine the height of the
object above the surface of the earth, in miles, for the object to register a weight of 125
pounds.

Answers

Answer:

The height of the  object is 5007.4 miles.

Explanation:

Given that,

Weight of object = 200 lb

We need to calculate the value of [tex]Gmm_{e}[/tex]

Using formula of gravitational force

[tex]F=\dfrac{Gmm_{e}}{r^2}[/tex]

Put the value into the formula

[tex]200=\dfrac{Gmm_{e}}{(3958.756)^2}[/tex]

[tex]200\times(3958.756)^2=Gmm_{e}[/tex]

[tex]Gmm_{e}=3.134\times10^{9}[/tex]

We need to calculate the height of the  object

Using formula of gravitational force

[tex]F=\dfrac{Gmm_{e}}{r^2}[/tex]

Put the value into the formula

[tex]125=\dfrac{200\times(3958.756)^2}{r^2}[/tex]

[tex]r^2=\dfrac{200\times(3958.756)^2}{125}[/tex]

[tex]r^2=25074798.5[/tex]

[tex]r=\sqrt{25074798.5}[/tex]

[tex]r=5007.4\ miles[/tex]

Hence. The height of the  object is 5007.4 miles.

Wanda is afraid of gaining weight and putting herself at high risk for disease. she works out on a regular basis and eats right most of time. recently, Wanda some testing done. her BMI with some 17.2 and her waist circumference is 30 inches. what statement best describes next move for Wanda so she will be at the least risk for disease?​

Answers

Answer:

C. Wanda's waist circumference indicates that she is not at risk, but her BMI indicates that she underweight. She should develop a plan to move her BMI into the normal range.

Explanation:

edge 2020 Brainliest would be appreciated

Answer:

Wanda's waist circumference indicates that she is not at risk, but her BMI indicates that she underweight. She should develop a plan to move her BMI into the normal range.

Explanation:

I just did the Cumulative Exam Review

Where is the magnetic south pole compared to the geographical north pole?

Answers

Currently, the magnetic south pole lies about ten degrees distant from the geographic north pole, and sits in the Arctic Ocean north of Alaska. The north end on a compass therefore currently points roughly towards Alaska and not exactly towards geographic north.

what happends when you slowly pull out the paper while theirs a coin on top​

Answers

The coin would probably slowly slide down whichever end it is closer to, weigh down the end of the paper, and fall off. It kinda depends on how you hold the paper though, because if it is directly in middle, and you hold it on both ends, it will stay on the paper.
The correct answer is “ the coin will stay on the same place on the paper and will move along with the paper “

Explain why the interconnection is not valid. Explain why the interconnection is not valid. A valid interconnection would require the 3 AA and 4 AA sources to supply different currents in the same direction, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply different currents in opposite directions, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply the same current in opposite directions, which they do not. A valid interconnection would require the 3 AA and 4 AA sources to supply the same current in the same direction, which they do not.

Answers

Complete Question

The diagram for this question is shown on the first uploaded image

Explain why the interconnection is not valid.

i A valid interconnection would require the 3 A and 4 A sources to supply different currents in the same direction, which they do not.

ii  A valid interconnection would require the 3 A and 4 A sources to supply different currents in opposite directions, which they do not.

iii  A valid interconnection would require the 3 A and 4 A sources to supply the same current in opposite directions, which they do not.

iv A valid interconnection would require the 3 A and 4 A sources to supply the same current in the same direction, which they do not

Answer:

The correct option is  iv

Explanation:

Looking at the diagram we see that the current source are connected in series, generally the current flowing through two source that are connected in series is suppose to be the same but in this case it is not so

i.e [tex]4A  \ne 3 A[/tex] hence Kirchhoff's law is broken or not followed in this circuit which means the interconnection is not valid  

also another reason why the interconnection is not valid is because the current are flowing in the different directions  

leaves uses_,_and_to make food for the plant​

Answers

light, water, carbon dioxide

Explanation:

c02 , h20 and light

Light water and carbon dioxide

Types of muscle tissue includes

Skeletal muscle

Cardiac muscle

Smooth muscle

All of the above

Answers

Answer:

D. all of the above

Explanation:

hope it helps

D. All of the above

URGENT!! A 0.057 kg tennis ball and a tennis racket collide. The racket has an initial
momentum of -2.80 kg m/s and a final momentum of -1.97 kg-m/s. The ball
has an initial momentum of 0.02565 kg-m/s. If you assume the collision is
elastic, what is the final velocity of the ball?
O A. -83.26 m/s
O B. -0.80 m/s
O C. -14.11 m/s
O D. -4.75 m/s

Answers

Answer:

-14.11

Explanation:

A tennis ball is released from a height of 2.0 m above the floor, and then bounces three times. With each bounce, dissipative forces cause it to lose 16.0% of its mechanical energy. How high does it reach after the third bounce?

140 cm

120 cm

120 mm

12 cm

Answers

Answer:

12 cm

Explanation:

From what I got with my answer (8.192 cm) I went ahead and rounded it to the closest answer which is 12 cm. Hopefully im correct but if not, I apologize in advance.

I would definitely say D: 12cm
Anything higher than i’d say 70 cm is false and it’s way to much. Thank you!!!

Work occurs when (2 points) an applied force results in movement of an object in the same direction as the applied force an object is subjected to balanced forces resulting in movement of the object the energy present is the result of the force acting on the object the movement of the object was caused by a force and is in the opposite direction of the force

Answers

Answer:

.

Explanation:

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