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
noname [10]
2 years ago
14

A railroad track and a road cross at right angles. An observer stands on the road and watches an eastbound train traveling at 60

meters per second. At how 70 meters south of the crossing. How many meters per second is the train moving away from the observer 4 seconds after it passes through the intersection?
Physics
1 answer:
mamaluj [8]2 years ago
4 0

Answer:

After 4 s of passing through the intersection, the train travels with 57.6 m/s

Solution:

As per the question:

Suppose the distance to the south of the crossing watching the east bound train be x = 70 m

Also, the east bound travels as a function of time and can be given as:

y(t) = 60t

Now,

To calculate the speed, z(t) of the train as it passes through the intersection:

Since, the road cross at right angles, thus by Pythagoras theorem:

z(t) = \sqrt{x^{2} + y(t)^{2}}

z(t) = \sqrt{70^{2} + 60t^{2}}

Now, differentiate the above eqn w.r.t 't':

\frac{dz(t)}{dt} = \frac{1}{2}.\frac{1}{sqrt{3600t^{2} + 4900}}\times 2t\times 3600

\frac{dz(t)}{dt} = \frac{1}{sqrt{3600t^{2} + 4900}}\times 3600t

For t = 4 s:

\frac{dz(4)}{dt} = \frac{1}{sqrt{3600\times 4^{2} + 4900}}\times 3600\times 4 = 57.6\ m/s

You might be interested in
What are the conditions under which the resultant of three coplanar forces is zero?<br>​
serg [7]
When three or more coplanar forces are acting at a point and the vector diagram closes, there is no resultant. The forces acting at the point are in equilibrium.
4 0
2 years ago
What is the conversion factor between km/h and mi/h
Aloiza [94]
<span> 1 mi = 1.609 km
so X mi/hr = 1.609 * X km/hr hope this helps!!</span>
5 0
3 years ago
What do you guys know about emotional intelligence? And how is it used in the real world?
tester [92]
Emotional Intelligence is our own abilities of being able to identify and regulate our own emotions. This is used by individuals in the real world in order to regulate crying in front of everyone for example. Calming ourselves down by breathing is another good example of regulating emotion which plays into emotional intelligence.

Hope this helps mate :D
7 0
2 years ago
Electrical energy is used to turn the blades of a fan. The amount of energy transformed is seen here : 750 J electrical energy i
Charra [1.4K]

Electrical energy is used to run the fan

Here as per given condition 750 J of electrical energy is used to run the fan which is converted into Kinetic energy as 400 J

So here we can see that 350 J of energy is lost against many other type of frictional and resistive loses.

So here we can say that out of 750 J of energy only 400 J is used to run the fan and rest amount of energy is lost against friction.

also we can say that efficiency of this fan will be

\eta = \frac{Useful}{Total}

\eta = \frac{400}{750}

\eta = \frac{8}{25}


3 0
2 years ago
How does a Freebody diagram tell you about the net force an object?
Sloan [31]
So you subtract the numbers that are on the same axis. So if your gravitational force is 10 and your normal force is 5 you do 5-10 to get -5 since gravity acts downward
6 0
3 years ago
Other questions:
  • A capacitor acquires a charge of 0.003 C when connected across a 30-V battery. Its capacitance is _____.
    10·1 answer
  • Which condition is characterized by the typical display of rigid behaviors that make it difficult for a person to get along with
    13·1 answer
  • Cart A and cart B are traveling in the same direction on a straight track. Cart A is moving at 9.25 m/s and cart B is moving at
    8·1 answer
  • You work for the city water department and need to pump 3400 liters/minute of water from a tank at ground level into a vented (i
    5·1 answer
  • P7.36 A ship is 125 m long and has a wetted area of 3500 m2. Its propellers can deliver a maximum power of 1.1 MW to seawater at
    15·1 answer
  • Here’s the picture of the problem
    15·1 answer
  • When buyers will purchase exactly as much as sellers are willing to sell, what is the condition that has been reached?
    8·1 answer
  • The discovery of photons is an example of which aspect of electromagnetic radiation?
    12·2 answers
  • 10. The table below shows the melting point and the boiling point of four substances.
    13·1 answer
  • In 1976, a 53 kg helicopter was built in Denmark. Suppose this helicopter flew east with a speed of 60.0 m/s and the total momen
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!