Question

(4) Not enough information is given
32. A stone falls from rest. The distance covered by it in the last second of its motion is equal to the distance covered
in the first three seconds. What is the height from which the stone was dropped? [Take g = 10 m/s)
(2) 100 m
(1) 25 m
(3) 125 m
(4) 200 m​

Answer 1

Answer:

Answer:

Explanation:

Distance traveled in first 3 seconds -

S= ut + 1/2(a*t^2)

S = 0.5 * 10 * 3^3

S = 45m

Distance traveled in last second = 45m

we know that distance traveled in ‘n’th second = Sn= u + a/2(2n-1)

45 = 0 + 10/2(2*n -1)

solve to get n = 5 seconds.

Therefore total time taken to reach the ground is 5 seconds.

S= ut + 1/2(a*t^2)

S = (0*5) + 1/2(10*5^2)

S = 0 + 1/2(10 * 25)

S = 125

Therefore the height from which the stone is dropped = 125m.

Hope this helped :)