Kinematics A car moving at 60km/h meets a train of length 1km

In summary, the distance traveled by the car when passing a 1km long train moving at 40km/h and a car moving at 60km/h is 3km when traveling in the same direction and 600m when traveling in the opposite direction. The equations used were S = ut + 1/2at^2 and relative speed = (v1 + v2) when traveling in the same direction and (v1 - v2) when traveling in opposite directions. Both answers were confirmed by a second opinion.
  • #1
monkfishkev
11
0

Homework Statement


A car moving at 60km/h meets a train of length 1km moving at 40km/h along a track parallel to the road. What distance does the car travel in passing the length of the train given that they travel a) in the same direction, or b) in opposite directions?

Homework Equations


So I converted everything into metres and used
S = ut + 1/2at^2

The Attempt at a Solution


By adding 1000m to s(displacement) of the car, managed to get 180seconds which gave 3km
In the opposite direction I got 36 seconds which gave 600m.

There was no answers given to the question set and really need a second opinion to these answers. They seem to make sense but I am still unsure.

Thank you
 
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  • #2


Looks good to me.
 
  • #3


The answers look right. I used the relative speed between car and train to calculate the time taken to pass the 1km long train, then worked out how far the car would travel along the ground in that time.
 

1. How is the speed of the car and train calculated?

The speed of the car and train can be calculated by dividing the distance traveled by the time taken. In this case, the distance is the length of the train (1km) and the time is the time it takes for the car to meet the train.

2. How do you determine the time it takes for the car to meet the train?

The time it takes for the car to meet the train can be determined by dividing the distance between them by the relative speed of the car and train. In this scenario, the distance between them is the sum of the length of the train (1km) and the distance traveled by the car (unknown). The relative speed is the sum of the car's speed (60km/h) and the train's speed (unknown).

3. What is the formula for calculating relative speed?

The formula for calculating relative speed is: relative speed = speed of object 1 + speed of object 2. In this case, the objects are the car and the train.

4. How do you convert the speed from km/h to m/s?

To convert from km/h to m/s, you can multiply the speed in km/h by 0.27778. In this scenario, the speed of the car is 60km/h, so when converted to m/s, it would be 16.67m/s.

5. What other factors should be considered when analyzing this scenario?

Other factors that should be considered when analyzing this scenario are the initial distance between the car and the train, the acceleration and deceleration of both the car and the train, and the potential impacts of external factors such as wind or road conditions on the speed and movement of the car and train.

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