Answers

2016-04-09T15:08:35+05:30
1st second

height of man = 1.8 m
height of the lamp = 4.5
 \frac{4.5}{1.8} \frac{5}{2}

2nd second 

height of man = 1.8 m
height of the lamp = 4.5
 \frac{4.5}{1.8} \frac{4.2+x}{x}
x = 2.8

3rd second

height of man = 1.8 m
height of the lamp = 4.5
 \frac{4.5}{1.8} \frac{5.4+x}{x}
x = 3.6

1st second, length of the shadow of man = 2 m

2nd second, length of the shadow of man = 2.8 m

3rd second, length of the shadow of man = 3.6 m

The length of the shadow of man = 0.8 m/s
0
Could u please explain why we should do like this
2016-04-09T18:42:26+05:30
For first second,
4.5/1.8 = 1.2 + x/x
4.5x = 21.6 + 1.8x
21.6 = 2.7x
x = 21.6/2.7
x = 8

For second second,
4.5/1.8 = 2.4 + x/x
x = 2.8

Rate = 2.8-8 = 0.8 m/s
0
But the answer is 0.4m/s
Oh sorry i forgot to didvide by two ^_^"