1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Vladimir79 [104]
3 years ago
12

Freight car A with a gross weight of 200,000 lbs is moving along the horizontal track in a switching yard at 4 mi/hr. Freight ca

r B with a gross weight of 100,000 lbs and moving at 6 mi/hr overtakes car A and is coupled to it. Determine: (a) the common velocity v of the two cars as they move together after being coupled, and (b) the loss of energy |DE| due to the impact.
Physics
1 answer:
zhenek [66]3 years ago
8 0

Answer: a) 4.7 mi/hr.  b) 86,500 lbs. mi²/Hr²

Explanation:

As in any collision, under the assumption that no external forces exist during the very small collision time, momentum must be conserved.

If the collision is fully inelastic, both masses continue coupled each other as a single mass, with a single speed.

So, we can write the following:

p₁ = p₂ ⇒m₁.v₁ + m₂.v₂ = (m₁ + m₂). vf

Replacing by the values, and solving for vf, we get:

vf = (200,000 lbs. 4 mi/hr + 100,000 lbs. 6 mi/hr) / 300,000 lbs = 4.7 mi/hr

If the track is horizontal, this means that thre is no change in gravitational potential energy, so any loss of energy must be kinetic energy.

Before the collision, the total kinetic energy of the system was the following:

K₁ = 1/2 (m₁.v₁² + m₂.v₂²) = 3,400,000 lbs. mi² / hr²

After the collision, total kinetic energy is as follows:

K₂ = 1/2 ((m₁ + m₂) vf²) = 3,313,500 lbs. mi²/hr²

So we have an Energy loss, equal to the difference between initial kinetic energy and final kinetic energy, as follows:

DE = K₁ - K₂ = 86,500 lbs. mi² / hr²

This loss is due to the impact, and is represented by the work done by friction forces (internal) during the impact.

You might be interested in
Explain how to determine the volume of an irregularly shaped object such as a rock
alexira [117]
If you have no way to accurately measure all of the object's bumps and dimples, then the only way to measure its volume is by means of fluid displacement. 

-- Put some water into a graduated (marked) container, read the amount of water, drop the object into the container, and read the new volume in the container.  The volume of the object is the difference between the two readings.

-- Alternatively, stand an unmarked container in a large pan, and fill it to the brim. Slowly slowly lower the object into the unmarked container, while the pan catches the water that overflows from it.  When the object is completely down in the container, carefully remove the container from the pan, and measure the volume of the water in the pan.  It's equal to the volume of the object.
6 0
3 years ago
An insulator can do which of the following? Conduct charge through it. Become positively or negatively charged. Transfer protons
ser-zykov [4K]
The correct answer is:
<span>Become positively or negatively charged

In fact, an insulator is a material where charges cannot move freely. Therefore, it can be positively or negatively charge (for example, if it is rubbed against another object, the insulator can remain with an excess of charge), but it cannot transfer charge to other objects.</span>
5 0
3 years ago
A spring gun is made by compressing a spring in a tube and then latching the spring at the compressed position. A 4.87-g pellet
Serga [27]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The work done by the spring is = 0.27 J

Explanation:

Force = torque × length

Given

F = 9.13 N

length (L) = 5.91 cm  = 0.0591 m                         [Note 1 m = 100 cm ]

considering the formula above

          9.13 = k * 0.0591    where k denotes torque

          k = 154.48\ N/m

Energy Stored  = \frac{1}{2} k x^2

                          = \frac{1}{2} * 154.48 * (0.0591)^2

                         = 0.27J  

8 0
3 years ago
It takes 56.5 kilojoules of energy to raise the temperature of 150 milliliters of water from 5°C to 95°C. If you
Debora [2.8K]
You'd get an extra 40/60 of the energy, or 2/3. Multiply 5/3 by the required energy to get the actual consumption.
7 0
2 years ago
A book is resting on the table. Forces are exerted _____.
scoray [572]
Forces are exerted I believe : all of the above
The action force might be Tyler throwing the ball
I don't know the last one
3 0
3 years ago
Read 2 more answers
Other questions:
  • A locomotive moved 18.0 m [W] in a time of 6.00 s and stopped. After stopping, the locomotive moved 12.0 m [E] in 10.0 s. a. Det
    13·1 answer
  • What would be the result of voltage while joining 2 or more different voltages of batteries with parallel ? and explain me what
    6·1 answer
  • Which of the following does not affect gas pressure
    9·1 answer
  • What is the area of 12 1/2 and 17 1/5
    9·1 answer
  • Difference between constant speed and average speed
    11·1 answer
  • Calculate the peak voltage of a generator that rotates its 200-turn, 0.100 m diameter coil at 3600 rpm in a 0.800 T field.
    12·1 answer
  • HELP NOW PLS !!
    12·1 answer
  • What is the purpose of the antireflective coating on the glass layer of a solar
    8·2 answers
  • Difference between power ciruit and light circuit?
    8·1 answer
  • A skier stands at the top of a 50 meter slope. He then skis down the slope. What is his approximate speed at the bottom of the s
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!