Banner 0
Banner 1
Banner 2
Banner 3
Banner 4
Banner 5

Q.

A ball is dropped from the roof of a tower of height h . The total distance covered by it in the last second of its motion is equal to the distance covered by it in first three seconds. The value of  h in metres is  (g=10ms2)

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya

answer is 125.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Distance covered in the last one second i.e., distance covered in the nth second if the ball takes n seconds to hit the ground is 
x1=Snth=0+g2(2n1)    ….(1)
Distance covered in the first three seconds is 
X2=12g(3)2=9g2     ….(2)
Since  X1=X2
g2(2n1)=9g2
2n1=9
n=5s
So, total time taken by the ball to hit the ground is 5 s. So,
h=12gt2
h=12(10)(5)2=5(25)=125m
h=125 m
 

Watch 3-min video & get full concept clarity

Best Courses for You

JEE

JEE

NEET

NEET

Foundation JEE

Foundation JEE

Foundation NEET

Foundation NEET

CBSE

CBSE

score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

whats app icon