Complete question:
How much time will a 500 m long train take to cross a tree if it is moving at a speed of 72 km/h
(Hint: Take the length of the train as the distance.)
Answer:
The time taken for the train to cross a tree is 25 s.
Explanation:
Given;
length of the train, L = distance between the train and a tree, d = 500 m
speed of the train, v = 72 km/h
Convert the speed to m/s, since the unit of the distance is in meters;
[tex]v = 72\frac{km}{h} \ \times \ \frac{1 000 \ m}{1 \ km} \ \times \ \frac{1 \ h}{60 \ \min} \ \times \ \frac{1 \ \min}{60 \ s} = \frac{(72 \times 1000) \ m}{(60\times 60) \ s} = 20 \ m/s[/tex]
The time of the motion is calculated as;
[tex]time = \frac{distance}{speed} \\\\time =\frac{500 \ m}{20 \ m/s} \\\\time = 25 \ s[/tex]
Therefore, the time taken for the train to cross a tree is 25 s.
