Physics, 26.10.2019 04:43 rbgrh8183

Arailroad freight car rolls on a track at 3.50 m/s toward two identical coupled freight cars, which are rolling in the same direction as the first, but at a speed of 1.20 m/s. the first reaches the second two and all couple together. the mass of each is 2.65 ✕ 104 kg. (a) what is the speed (in m/s) of the three coupled cars after the first couples with the other two?

Answers: 2

Show answers

Answers

Answer from: jamilamiller200

Explanation:

Hello! To solve this problem we must be clear about the concept of energy conservation, and kinetic energy with the following sentence

The kinetic energy of the two cars (v = 1.2m / S) plus the kinetic energy of the third car (v = 3.5m / S) must be equal to the kinetic energy of the three cars together.

The kinetic energy is calculated by the following equation.

E=0.5mV^2

m= mass of the cars=26500kg

V=speed

E=kinetic energy

taking into account the above, the following equation is inferred

1= the cars are separated

2= the cars are togheter

E1=E2

E1=0.5mV1^2+0.5mV1^2+0.5m(Va)^2

where

m= mass of each car

V1= 1.2m/s

Va=3.5,m/S

E2=0.5(3)(m)V^2

m= mass of each car

V=speed (in m/s) of the three coupled cars after the first couples with the other two

Solving

0.5mV1^2+0.5mV1^2+0.5m(Va)^2=0.5(3)(m)V^2

$V1^2+V1^2+(Va)^2=(3)V^2.\\2V1^2+(Va)^2=(3)V^2\\V^2=\frac{2V1^2+(Va)^2}{3} \\$

$V=\sqrt{\frac{2V1^2+(Va)^2}{3}} \\V=\sqrt{\frac{2(1.2)^2+(3.5)^2}{3}} \\\\V=2.245m/s$

the speed of the three coupled cars after the first couples with the other two is 2.245m/s

Answer from: xojade

1.97 m/s

Explanation:

Recall that from the principle of conservation of energy, p = mv

$p_{1} + p_{23} = p_{123}$ ----- eqn 1

Total momentum before collision equals total momentum after collision

sub mv for p in eqn 1

$m_{1}v_{1} + m_{23}v_{23} = m_{123}v_{123}$ ----- eqn 2

Parameters

$m_{1} = m_{2} = m_{3} = 2.65 X 10^{4} kg$

$m_{23} = 5.3 X 10^{4} kg$

$m_{123} = 7.95 X 10^{4} kg$

$v_{1} = 3.50 m/s$

$v_{23} = 1.20 m/s$

$v_{123} = ?$

Where $v_{123}$ is the speed of the three coupled cars

substitute for all m and v in eqn 2

$(2.65 X 10^{4} X 3.5) + (5.3 X 10^{4} X 1.2) = (7.95 X 10^{4} X v_{123})$

$(9.275 X 10^{4} + 6.36 X 10^{4}) = (7.95 X 10^{4} X v_{123})$

$15.635 X 10^{4} = 7.95 X 10^{4} X v_{123}$

$v_{123}$ = $\frac{15.635 X 10^{4}}{7.95 X 10^{4}}$

$v_{123}$ = 1.9667 m/s

Therefore, the speed of the three cars after coupling is 1.97m/s

Answer from: Quest

when it gains or loses electrons

Answer from: Quest

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this

Another question on Physics

Physics, 22.06.2019 11:10

Assume this car is driven off a cliff . how many arrows of force need to be drawn in the free body diagram? assume no air resistance -five -one -three -four

Answers: 1

Answer

Physics, 22.06.2019 11:30

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

Answers: 1

Answer

Physics, 22.06.2019 14:00

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.

Answers: 1

Answer

Physics, 22.06.2019 18:30

Acar starts from rest at a stop sign and reaches a velocity of 25 m/s w in 4 seconds. determine the acceleration of the car. question 3 options: a) 6,25 m/s2 b)6.25 m/s c)100 m/s2 d)100 m/s

Answers: 1

Answer

You know the right answer?

Arailroad freight car rolls on a track at 3.50 m/s toward two identical coupled freight cars, which...

Questions