Question

A body released from the top of a tower falls through
a height of 5m during the first second of its fall and
35m during the last second of its fall. The height of
the tower is
(A) 80 m
(B) 60 m
(C) 40m
(D) 20 m​

Answer 1

Answer:

the answer will be 40

Answer 2

Answer:

A)=80m

Explanation:

In this Question,

We have been given that

A body is released from top of the Tower,it falls 5m during 1st second and 35m during last second of its fall

We need to find the height of the tower

As we know Distance travelled in the nth second is $s_{n}=u+\frac{a}{2}(2n-1)$

As body starts from rest so initial velocity so u = 0

Taking Acceleration as 10$m/s^{2}$

putting the values we get,

35=0+5(2n-1)

7=2n-1

n=4

So total time taken will be 4 seconds

Now finding the height of the tower we get,

$s=ut+\frac{1}{2}at^{2}$

as u=0

Therefore S$=\frac{1}{2}\times 10\times (4)^{2}$

S=80metres

Therefore total height of the tower is 80m