A girl of height 90 cm is walking away from the base of the lamp post at a speed of 1.2 m/sec. If the lamp post is 3.6 m above the ground, find the length of her shadow after 4 seconds.
Answers
✰ Qᴜᴇsᴛɪᴏɴ :-
A girl of height 90 cm is walking away from the base of the lamp post at a speed of 1.2 m/sec. If the lamp post is 3.6 m above the ground, find the length of her shadow after 4 seconds.
☢ Gɪᴠᴇɴ :-
- Height of the lamp post = 3.6 m
- Speed of the girl = 1.2 m/sec
✦ Tᴏ Fɪɴᴅ :-
- Length of her shadow after 4 seconds
✪ Sᴏʟᴜᴛɪᴏɴ :-
❝ ʀᴇғᴇʀ ᴛʜᴇ ᴀᴛᴛᴀᴄʜᴍᴇɴᴛ ғᴏʀ ᴛʜᴇ ᴅɪᴀɢʀᴀᴍ ❞
Distance travelled in 4 sec = Speed × Time
⇒ 1.2 × 4
⇒ 4.8 m
⇒ 480 cm
- Height of the girl (CD) = 90 cm
Let the length of the shadow at a distance of 4.8m from the lamp post = x cm
From the diagram,
∆ABE ∼ ∆DCE
∵ ∠B = ∠C = 90°
∠E = ∠C common
(A.A. similarity)
Hence, AB/DC = BE/CE = AE/DE
∴ 360/90 = 480 + x / x
➸ 4 = 480 + x / x
➸ 4x = 480 + x
➸ 4x - x = 480
➸ 3x = 480
➸ x = 480/3
➸ x = 160cm
➸ x = 1.6m
⛬ Length of the shadow = 1.6 m
Qᴜᴇsᴛɪᴏɴ ✔
✯.A girl of height 90 cm is walking away from the base of the lamp post at a speed of 1.2 m/sec. If the lamp post is 3.6 m above the ground, find the length of her shadow after 4 seconds.
FORMULA IN USED,
✯conversion,
✯ACCORDING TO THE QUESTION,
THEREFORE,
NOW,