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valina [46]
3 years ago
13

At the train station, you notice a large horizontal spring at the end of the track where the train comes in. This is a safety de

vice to stop the train so that it will not plow through the station if the engineer misjudges the stopping distance. While waiting, you wonder what would be the fastest train that the spring could stop at its full compression which is L=3 ft . To keep the passengers safe when the train stops, you assume a maximum stopping acceleration of g/2. You also guess that a train weighs half a million lbs. For purpose of getting an estimate, you decide to assume that all frictional force are negligible.I've already posted this and someone gave me the wrong answer and i cannot for the life of me figure it out. The answer is not 7.66 m/s and should not be in meters, as the question gives everything else in feet.
Physics
1 answer:
xxMikexx [17]3 years ago
8 0

Answer:

  v₀ = 9,798 ft / s

Explanation:

We can solve this problem with kinematics in one dimension, when the train stops the speed is zero, the acceleration is negative so that the train stops. Let's use the equation

         v² = v₀² - 2 a d

         v = 0

         v₀ = √2 a d

In the problem it indicates that the acceleration is g / 2, we substitute

         v₀ = √2 (g / 2) d

Let's calculate

         v₀ = √ 2 32/2 3 = √32 3

         v₀ = 9,798 ft / s

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Dimas [21]

Answer:

<em>10.90km</em>

Explanation:

Magnitude of the total displacement is expressed using the equation

d = √dx²+dy²

dx is the horizontal component of the displacement

dy is the vertical component of the displacement

dy = -6.7sin27°

dy = -6.7(0.4539)

dy = -3.042

For the  horizontal component of the displacement

dx = -4.5 - 6.7cos27

dx = -4.5 -5.9697

dx = -10.4697

Get the magnitude of the bicyclist's total displacement

Recall that: d = √dx²+dy²

d = √(-3.042)²+(-10.4697)²

d = √9.2538+109.6146

d = √118.8684

<em>d = 10.90km</em>

<em>Hence the magnitude of the bicyclist's total displacement is 10.90km</em>

<em></em>

6 0
2 years ago
A flea walking along a ruler moves from the 45 cm mark to the 27 cm mark. It does this in 3 seconds. What is the speed? What is
Alekssandra [29.7K]

Answer:

Speed= 6cm/s and velocity= 6cm/s in the negative direction

Explanation:

the change in position is from 45cm to 27 cm (moving towards the negative x direction)

\Delta x = 45 cm - 27 cm = 18 cm

And the change in time:

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Now we must define the difference between speed and velocity:

Speed is a scalar quantity, which means that it is a number. Velocity ​​is also a number but you must also indicate the direction of the movement.

Thus, the speed is:

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An the velocity is:

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Momentum is simply defined as the product of mass and velocity. Mathematically, it can be expressed as:

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With the above formula, the momentum of train car A before collision can be obtained as follow:

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5 0
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