A train 90 m long is travelling at a speed of 40 kmph. A man is running at a speed of 5 kmph in a direction opposite to the motion of the train. What would be the time taken by the train to cross the man?
Answers
Answer:
Length of the train = 90 m = Distance
Speed of the train = 40 km/h
= 40 x 5/18
= 200/18 m/s
Speed of the man in opposite direction = 5 km/h
= 5 x 5 /18
= 25/18 m/s
Relative speed of the train = 200/18 + 25/18
= 225 / 18 m/s
Time taken by train to cross the man = Distance/Speed
= (90 x 18) / 225
= 7.2 sec.
ANSWER IS 36/5 OR 7.2 SEC
Explanation:
Answer:
Time taken by the train to cross the man is 7.2s.
Relative velocity: It is the velocity of an object with respect to an observer.
Mathematically it is defined as If two objects are traveling with a speed of V₁ and V₂ then their relative velocity V₁₂ = V₁ - V₂.
Relation to be noted:
1 kmph = 5/18 m/s
Explanation:
Given the length of the train = 90m
velocity of the train = 40 kmph = 40*5/18 m/s
velocity of the man = -5 kmph = 5*5/18 m/s
velocity of the train with respect to the man 45*5/18 m/s
Time taken to cross the man = 90/45 * 18/5 = 7.2s