Question

a stone is dropped from a height of 45 metre the distance travelled by it during the last 1 second of its motion is g is equal to 10 m per second square

Answer 1

total time taken=(2h/g)1/2 = (2*45/10) ½  = (9) ½ = 3

distance travelled in last sec = S= u + a/2 (2n-1)

S= 0 + 10/2 (2*3 – 1)

= 25 m

Answer 2

initial velocity =0
so s=1/2gt^2
45=1/2*10t^2
9=t^2
t=3sec
now distance covered at last 1second=45-1/2*10*2^2
=45-20=25meter Answer