﻿ Solving problem

# Problems to solve

## Theme n°1 : Kinematics

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Name Age Country Problem Answer to the problem
Problem 1 N.P 17 France How long, is a train of length L1=450m going to travel a bridge of length L2=150 m? The speed of the train is 72 km/h. Registrate to solve this problem
Problem 2 N.P 17 France A line of automobiles of length L=0,7 km moves with a speed of V1=54 km/h. The first motorcycle of the line decides to go to join the tail of the column then, returns immediately at the head of the line. Knowing that during this round trip, the speed of the motorcycle V2=30 m/s remained constant. How long, the motorcycle is going to make this round trip? Registrate to solve this problem
Problem 3 N.P 17 France During the first half of the lenght of the route, a car moves at a speed V1=75 km/h. During the second half of the lenght of the route, this car moves at a speed V2=50 km/h. What is the average speed of the car? Registrate to solve this problem
Problem 4 N.P 17 France During the first part of the time of route, a car moves in a speed V1=90 km/h. During the second part of the time of route, this car moves in a speed V2=50 km/h. What is the average speed of the car? Registrate to solve this problem
Problem 5 N.P 17 France An object in free-fall without initial speed, went through a height h. During the last second of its fall, it went through a height Δh equal to 3/4 of the total height. How long lasted this fall? Registrate to solve this problem
Problem 6 N.P 17 France A motionless train at first, accelerates in a constant way. Near the passenger situated in the "head" of the train, the 1st wagon of the train passed in 10 seconds. How long, passed all the train compound of 16 wagons? Registrate to solve this problem
Problem 7 N.P 17 France An object falls freely of a height h=315 meters. How long does it fall during the last 140 meters of its fall?
Registrate to solve this problem
Problem 8 N.P 17 France An object falls freely of a height h=490 meters. What distance is it going to fall during the last 2 seconds of fall? Registrate to solve this problem
Problem 9 N.P 17 France A plane flies horizontally with a speed V=470 m/s. A man hears the noise of the plane 21 seconds after the passage of the plane above him. From what height flies the plane? Speed of sound: C = 330 m/s. Registrate to solve this problem
Problem 10 N.P 17 France On the two directions railroad, 2 trains meet: first train of length L1=300 meters and speed V1=20 m/s; second train of length L2=400mètres and speed V2=15 m/s. How long separates the moment T1 where the train heads meet, and T2 the moment when their last wagons separate? Registrate to solve this problem