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rodikova [14]
3 years ago
8

A railroad car of mass 2.52 104 kg is moving with a speed of 3.86 m/s. It collides and couples with three other coupled railroad

cars, each of the same mass as the single car and moving in the same direction with an initial speed of 1.93 m/s. (a) What is the speed of the four cars after the collision? (Round your answer to at least two decimal places.) m/s (b) How much mechanical energy is lost in the collision?
Physics
1 answer:
aleksley [76]3 years ago
6 0

Answer:

a)   v = 2.4125 m / s  , b)  Em_{f} / Em₀ = 0.89

Explanation:

a) This is an inelastic crash problem, the system is made up of the four carriages, so the forces during the crash are internal and the moment is conserved

Initial

          p₀ = m v₁ + 3 m v₂

Final

         p_{f} = (4 m) v

        p₀ =p_{f}

        m (v₁ + 3 v₂) = 4 m v

        v = (v₁ +3 v₂) / 4

Let's calculate

       v = (3.86 + 3 1.93) / 4

       v = 2.4125 m / s

b) the initial mechanical energy is

       Em₀ = K₁ + 3 K₂

       Em₀ = ½ m v₁² + ½ 3m v₂²

       

The final mechanical energy

         Em_{f} = K

         Em_{f} = ½ 4 m v²

The fraction of energy lost is

          Em_{f} / Em₀ = ½ 4m v² / ½ m (v₁² +3 v₂²)

          Em_{f} / Em₀ = 4 v₂ / (v₁² + 3 v₂²)

          Em_{f} / Em₀ = 4 2.4125² / (3.86² + 3 1.93²)

          Em_{f} / em₀ = 23.28 / 26.07

          Em_{f} / Em₀ = 0.89

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Answer:
A financial manager.

Explanation:
This is because a financial manager oversees the financial operations of a company. Generally, a financial manager assumes accounting responsibilities for the company. A financial manager is responsible for planning and managing the company's financial resources.


Side note:
Hope this helps!
Please give Brainliest!
6 0
2 years ago
If the 80 ohm resistor fails, will the 50 ohm and 100 ohm resistor continue to operate? Why or why not?
sleet_krkn [62]

Answer:

No, the 50 ohm and 100 ohm resistor will not continue to operate.

Explanation:

A closed circuit is the circuit in which there is no break between the negative and the positive end of the battery.

When in this, combinational circuit the 80 ohm resistor fail then there will not any continue supply of current in the circuit due to the breakage because the electron will flow from negative end of the battery to positive end if their is no breaking in the circuit.

Therefore the 50 ohm and 100 ohm circuit will not continue to operate because of the breaking of the circuit and current will not flow.

7 0
3 years ago
Many battery-powered devices come with cords that allow them to be
lara [203]

Answer:

The change that has to take place inside the power cord in order for the device to function properly include;

The changing of the alternating current (AC) from the electrical outlet to the direct current having a specific voltage and current value with which the device can be powered

Explanation:

A battery powered device makes use of direct current (DC) electric power from a battery, while the power normally given out at an electrical outlet comes as an alternating current (AC) electric power source.

The power cord for battery-powered device, also known as an AC/DC adapter, that allows them to be plugged into electrical outlets converts the AC electric current it obtains from the electrical outlets to DC electrical current of the appropriate voltage and amperage that the device can make use of for electric power to function and for charging the battery which is the power source for the device

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4 0
2 years ago
You leave on a 450 miles trip in order to attend a meeting that will start 10.8 hours after you begin your trip. Along the way y
konstantin123 [22]

Answer:

c. 2.6 h

Explanation:

The longest time spent over dinner is the time that you have available minus the minimum possible time spent in the trip.

The time of the trip is found using:

t = \frac{d}{v}

Where distance is d and velocity is v. The time will be minimum at maximum velocity. Replacing with the data we have:

Ttrip = \frac{450}{55} = 8.1818 h

Tdinner = 10.8h - 8.1818 h = 2.6181h

that aproximates 2.6 h.

4 0
3 years ago
How much work is done lifting a 12-m chain that is initially coiled on the ground and has a density 2 kg/m so that its top end i
Misha Larkins [42]

Answer:

2587.2 J.

Explanation:

From potential energy,

The work done to lift the chain = potential energy of the chain.

W = mgh............... Equation 1

Where W = work done to lift the chain, m = mass of the chain, g = acceleration due to gravity of the chain, h = height of the chain.

But,

m = m'd............... Equation 2

Where m' = density of the chain, d = length of the chain.

Substitute equation 2 into equation 1

W = m'dgh................ Equation 3

Given: m' = 2 kg/m, d = 12 m, h = 11 m, g = 9.8 m/s²

Substitute into equation 3

W = 2(12)(11)(9.8)

W = 2587.2 J.

3 0
3 years ago
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