Question

A particle starts sliding down a frictionless inclined plane. If Sn is the distanc
Sn is the distance travelled by it from time
t=n-1 second to t= n second, the ratio S/Sn+1 is :
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Answer 1

Answer:

Explanation:

use the equations of motion:  s = ut + 1/2 a t^2

let Ф be the angle of the inclined plane with the horizontal.

Acceleration along the inclined plane = g sin Ф

Let initial velocity at t = 0 sec, be u = 0 m/s.

  

distance travelled up to n-1 sec:  D(n-1) = 1/2 g SinФ * (n-1)²

distance travelled up to  n sec. :  D(n) = 1/2 * g Sin Ф * n²

Distance travelled upto n+1 sec:  D(n+1) = 1/2 * g Sin Ф * (n+1)²

 Sn = Distance travelled from t = n -1 sec. to  n sec. = 1/2 g Sin Ф * [n² - (n-1)²]

       = 1/2 g Sin Ф * (2n - 1)

Sn+1  = distance travelled from t = n sec to n+1 sec = 1/2 g Sin Ф * (2n +1)

Ratio :  Sn / Sn+1  =  (2n -1) / (2n +1)  = 1 - 1 / (n +1/2)