Answer to Question #165413 in Physics for Hadjer

Question

Exercise 2:

1- Two trains will travel on the same straight rail and head towards each other. Speed ​​of one of them is 130Km / h and the speed of the second is 0K / h 10 for the rail. About 3km away, the two drivers both noticed the error, and each began to halt their train. If each train slowed by 1 ° m / s, would they collide? 2- At a distance d in front of him, a driver of a train with speed V sees another train

Ethe V2 and head

It runs on the same straight rail in the same direction as the first train. The driver is running

The brakes

The train is slowing down by a constant a. What is the condition that the two trains do not collide?

Answer 1

$$u=v_1+v_2\\t=\frac{u}{a}=\frac{130+100}{3.6\cdot1}=36.9\ s$$

$$s=ut-0.5at^2\\s=\frac{130+100}{3.6}(36.9)-0.5(1)(36.9)^2=2041\ m$$

It is less than 3 km. Thus, the trains will not collide.