A girl of height 120cm is walking away from the base of a lamp post at a speed of 0.6m/sec. If the lamp is 3.6m above the ground level , then find the length of her shadow after 4 seconds.
Answers
Answer:
The length of the shadow will be 1.2 m
Step-by-step explanation:
height of the girl = 120 cm = 1.2 m
height of the lamp = 3.6 m
Let the shadow length = x
distance traveled by the girl in 4 second = 0.6 x 4 = 2.4 m
from the properties of similar triangle;
1.2/3.6 = x /( x + 2.4)
=> 3x = x + 2.4
=> 2x = 2.4
=> x = 1.2 m
Hence the length of the shadow will be 1.2 m
Answer:
length of her shadow after 4 seconds 1.2
Step-by-step explanation:
From the figure attached with this answer,
AB be the lamp of 3.6m height.
Let x be the length of shadow.
To find the distance after 4 seconds
It is given that, the speed of girl is 0.6m/sec.
∴ After 4 seconds she covered the distance = speed x time
distance = 0.6 x 4 = 2.4 m
From the figure CD shows the girl.
To find the length of shadow
From the figure we get,
CF = AF = 2.4 m and <FAC= <FCA = 45°
<FAC = <DEC = 45°
Therefore tanθ= CD/x
tan 45= 1.2/x
1 = 1.2/x
∴ x = 1.2 m
