Question

The distance travelled by a body falling from the rest in one second, two seconds and three seconds are after 5 seconds from the start. The height of an above the ground is? ( g= 10 m/s^2)
a) 1:2:3 b)3:2:1 c)1:4:9 d)9:4:1​

Answer 1

Correct option is

B )1:3:5

Initial velocity of the body  u=0

Distance covered in tth second,  St​=u+21​g(2t−1)

∴  St​=0+21​g(2t−1)=21​g(2t−1)

Distance travelled in first second i.e. t=1, S1​=21​g(2×1−1)=21​g

Distance travelled in 2nd second i.e. t=2, S2​=21​g(2×2−1)=23​g

Distance travelled in third second i.e. t=3,  S3​=21​g(2×3−1)=25​g

⟹  S1​:S2​:S3​=1:3:5