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
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

You might be interested in
a concrete slab 20 m long and weighing 400,000 N is supported by one pillar. If a 19,600 N car is parked 8 meters from one end.
LUCKY_DIMON [66]

let the distance of pillar is "r" from one end of the slab

So here net torque must be balance with respect to pillar to be in balanced state

So here we will have

Mg(r - L/2) = mg(L/2 - 8)

here we know that

mg = 19600 N

Mg = 400,000 N

L = 20 m

from above equation we have

400,000(r - 10) = 19,600 (10 - 8)

r - 10 = 0.098

r = 10.098 m

so pillar is at distance 10.098 m from one end of the slab

7 0
3 years ago
Convert 141.2 kg to lbs and show all units and work​
zavuch27 [327]
Your answer is 311.29271 lbs
5 0
3 years ago
The angle between the two force of magnitude 20N and 15N is 60 degrees (20N force being horizontal) determine the resultant in m
BARSIC [14]

A) The resultant force is 30.4 N at 25.3^{\circ}

B) The resultant force is 18.7 N at 43.9^{\circ}

Explanation:

A)

In order to find the resultant of the two forces, we must resolve each force along the x- and y- direction, and then add the components along each direction to find the components of the resultant.

The two forces are:

F_1 = 20 N at 0^{\circ} above x-axis

F_2 = 15 N at 60^{\circ} above y-axis

Resolving each force:

F_{1x}=F_1 cos \theta = (20)(cos 0)=20 N\\F_{1y}=F_1 sin \theta =(20)(sin 0)=0 N

F_{2x}=F_2 cos \theta = (15)(cos 60)=7.5 N\\F_{2y}=F_2 sin \theta =(15)(sin 60)=13.0 N

So, the components of the resultant are:

F_x = F_{1x}+F_{2x}=20+7.5 = 27.5 N\\F_y = F_{1y}+F_{2y}=0+13.0=13.0 N

And the magnitude of the resultant is:

F=\sqrt{F_x^2+F_y^2}=\sqrt{27.5^2+13.0^2}=30.4 N

And the direction is:

\theta=tan^{-1}(\frac{F_y}{F_x})=tan^{-1}(\frac{13.0}{27.5})=25.3^{\circ}

B)

In this case, the 15 N is applied in the opposite direction to the 20 N force. Therefore we need to re-calculate its components, keeping in mind that the angle of the 15 N force this time is

\theta=180^{\circ}-60^{\circ}=120^{\circ}

So we have:

F_{2x}=F_2 cos \theta = (15)(cos 120)=-7.5 N\\F_{2y}=F_2 sin \theta =(15)(sin 120)=13.0 N

So, the components of the resultant this time are:

F_x = F_{1x}+F_{2x}=20-7.5 = 12.5 N\\F_y = F_{1y}+F_{2y}=0+13.0=13.0 N

And the magnitude is:

F=\sqrt{F_x^2+F_y^2}=\sqrt{13.5^2+13.0^2}=18.7 N

And the direction is:

\theta=tan^{-1}(\frac{F_y}{F_x})=tan^{-1}(\frac{13.0}{13.5})=43.9^{\circ}

Learn more about vector addition:

brainly.com/question/4945130

brainly.com/question/5892298

#LearnwithBrainly

7 0
3 years ago
Suppose a scientist conducts a series of experiments and the results are so amazing she wants to share them with other experts i
nataly862011 [7]

Answer:

The results have not been through the rigorous process of peer review

Explanation:

When a scientist conducts a study and obtains results, those results ought to be submitted to a reputable journal where the results would go through the rigorous protocol of peer review.

During this process, the reliability of the data presented is ascertained before the results are published for other scientists to see.

If the results are hurriedly published on the internet, many researchers who come in contact with the work may be fed with inaccurate information.

7 0
3 years ago
The train 'A' travelled a distance is f 120 km in 3 hours , Whereas another train 'B' travelled a distance of 180 km in 4 hours
Radda [10]

Answer:

B train!

Explanation:

A train travelled at 40 km/hr. (120/3)

B train traveled at 45 km/hr (180/4)

6 0
3 years ago
Read 2 more answers
Other questions:
  • A rock dropped on the moon will increase it's speed from 0 m/s to 8.15 m/s in about 5 seconds what is the acceleration of the ro
    10·1 answer
  • Which best describes how geothermal energy is used to make electricity?. . A.. Rocks are split to release energy that drives a s
    12·1 answer
  • Much of the bedrock in Virginia’s Piedmont region, originally formed by cooled magma, has re-crystallized under a great deal of
    6·1 answer
  • Some plants disperse their seeds when the fruit splits and contracts, propelling the seeds through the air. The trajectory of th
    14·2 answers
  • Describing Changes of State
    8·1 answer
  • A baby stroller is a rest on top of a hill which is 10 m high. The stroller and baby have a mass of 20 kg. What is the potential
    11·2 answers
  • A gas’ pressure is 1.3 atm at 23 degrees Celsius. At what temperature will the pressure be 0.75 atm?
    7·1 answer
  • a projectile is fired from the ground with an initial horizontal velocity of 8 meters per second. its initial vertical velocityi
    11·1 answer
  • If a Ferrari, with an initial velocity of 10 m/s,
    9·1 answer
  • In the following description, QUOTE the portion that addresses weather in the area.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!