Here         u  = 100 m/s

            v = 0,       s = 1 cm = `10^-2` m

`:.`        ` v^2 = u^2 - 2as`

`:.`         `a =( u^2)/(2s)  = (100 xx 100)/(2 xx 1 xx 10^-2`

     = `5 xx 10^5` m / `s^2`

`:.`    F = ma = `10 xx 10^-3 xx 5 xx 10^5` = 5000  N

Alternative method

              `W = Delta `K

`or      - Fs = 1/2 mv^2 - 1/2 mu^2`

                   = `0 - 1/2 xx 10 xx 10^-3 xx 10000`

or      `- F xx 10^-2 = - 1/2 xx 10  xx 10^-3 xx 10 ^4`

`:.`              F = 5000 N.