Banner 0
Banner 1
Banner 2
Banner 3
Banner 4
Banner 5
Banner 6
Banner 7
Banner 8
Banner 9

Q.

A stone is dropped from the top of a tower of height ‘H’ ,in last second of journey it travels a distance of  0.36 H. Then   height H and time of fall of stone  is g=10m/s2

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.
An Intiative by Sri Chaitanya

a

2050m, 10s

b

125m, 5s

c

150m, 7s

d

500m, 20s

answer is B.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

JEE

NEET

NEET

Foundation JEE

Foundation JEE

Foundation NEET

Foundation NEET

CBSE

CBSE

Detailed Solution

Let ‘n’ is last sec Sn is distance covered in last secwe know, S=Ut+12at2, here  displacement=s=H;  initial velocity=U=0;  acceleration due to gravity=a=g; total time elapsed=t=n; substitute given values in the equation      H=12gn2---(1)  Distance travelled before the last second  =H−0.36H=0.64Hdistance covered before last second=12gn−12=0.64H substitute equation (1) ⇒12gn−12=0.6412gn2 ⇒0.64n2=n−12 ⇒0.64n2=n−12⇒64100n2=n−12⇒8n=10n−10⇒2n=10⇒n=5⇒n=5=total time of flight The time of fall is 5sec  h=12gn2 ⇒h=121052 ⇒h=2502 ⇒h=125m=height of tower
Watch 3-min video & get full concept clarity
score_test_img

courses

No courses found

Get Expert Academic Guidance – Connect with a Counselor Today!

best study material, now at your finger tips!

  • promsvg

    live classes

  • promsvg

    progress tracking

  • promsvg

    24x7 mentored guidance

  • promsvg

    study plan analysis

download the app

gplay
mentor

Download the App

gplay
whats app icon
personalised 1:1 online tutoring