Q.

A small block slides down on a smooth inclined plane, starting from rest at time t=0. Let Sn be the distance travelled by the block in the interval t=n-1 to t=n. Then, the ratio SnSn+1 is                  [2021]
 

1 2n2n-1  
2 2n-12n  
3 2n-12n+1  
4 2n+12n-1  

Ans.

(3)

The acceleration is a=gsinθ

Initial velocity, u=0

Distance travelled in nth second Snth=u+12a(2n-1)

            Snth=12a(2n-1)                                                  ...(i)

            S(n+1)th=12a[2(n+1)-1]                                 ...(ii)

On dividing eqn (i) by (ii), we get

   SnthS(n+1)th=(2n-1)(2n+1)