Q.

The distances covered by a freely falling body in its first, second, third, ..., nth seconds of its motion

1 forms an arithmetic progression  
2 forms a geometric progression  
3 do not form any well defined series  
4 form a series corresponding to the difference of square root of the successive natural numbers  

Ans.

(1)

Distance travelled by a body in nth second is

Dn=u+a2(2n-1)

Here, u=0, a=g

∴  Distance travelled by the body in 1st second is

D1=0+g2(2×1-1)=12g

Distance travelled by the body in 2nd second is

D2=0+g2(2×2-1)=32g

Distance travelled by the body in 3rd second is

D3=0+g2(2×3-1)=52g  and so on.

Hence, the distances covered by a freely falling body in its first, second, third, ......, nth second of its motion forms an arithmetic progression.