Calculating Relative Velocity: Train vs. Car Collision

In summary, relative velocity is the velocity of an object in relation to another object, taking into account their motion and positions relative to each other. It differs from absolute velocity, which is the velocity of an object in relation to a fixed point. Relative velocity can be calculated by finding the difference between the velocities of two objects or using vector addition. It can be negative when the direction is opposite to the motion of the objects. In collisions, relative velocity can determine the outcome and intensity. In real life, it has various applications such as navigation, transportation, and sports.
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kidgt23
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Homework Statement


A person on a train watches a car approaching a railway crossing ahead on his track. It appears that the car’s driver has fallen asleep and will not slow down. The train is traveling north‐east at 100km/h while the car is going west at 80km/h. The train is 4 km and the car is 3km from the crossing. I) What is the velocity of the car relative to the train. Pick the train travel direction (North‐ East) as the +x direction and the perpendicular direction (North‐west) as the +y direction II) Where will the train be when the car gets to the crossing, will they collide? III) Find the acceleration of the car required to cause a collision. IV) In the reference frame of the train rider, what is the acceleration.

Homework Equations

The Attempt at a Solution

 
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Hi kid, :welcome:

Is there a question here ? PF has a specific culture (read the guidelines) asking something from you ...
 
  • #3
could u solve it
 
  • #4
kidgt23 said:
could u solve it
In order to get help you need to show your best attempt to solve the problem and explain where you get stuck. We can just do the problem for you.
 

What is relative velocity and how does it differ from absolute velocity?

Relative velocity is the velocity of an object in relation to another object. This means it takes into account the motion of both objects and their positions relative to each other. Absolute velocity, on the other hand, is the velocity of an object in relation to a fixed point or reference frame. It does not consider the motion of any other objects.

How is relative velocity calculated?

Relative velocity is calculated by finding the difference between the velocities of two objects. This can be done by subtracting the velocity of one object from the velocity of the other or by using vector addition. In vector addition, the velocities of the two objects are added together to find their combined velocity.

Can relative velocity be negative?

Yes, relative velocity can be negative. This occurs when the direction of the relative velocity is opposite to the direction of motion of the two objects. For example, if two cars are moving towards each other with velocities of 10 m/s and 5 m/s, the relative velocity between them would be -15 m/s.

How does relative velocity affect collisions?

Relative velocity plays a crucial role in determining the outcome of collisions between objects. The relative velocity at the point of impact can determine whether the collision is elastic or inelastic. A higher relative velocity can also result in a more intense collision with greater force and damage.

What is the application of relative velocity in real life?

Relative velocity has many practical applications in our everyday lives. It is used in navigation, such as determining the relative velocity of a boat in relation to the current. It is also important in transportation, such as calculating the relative velocities of planes and cars in traffic. Additionally, it is used in sports, such as determining the relative velocities of players in a game.

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