A bullet of mass `100 gram` moving with `20 m//s` Strikes a wooden plank and penetrates upto 20 cm. Calculate the resistance offered by the wooden plank .

Explanation

Here, ` m = 100 g = 10^(-1) kg` ,
`upsilon = 20 m//s`
`x = 20 cm = (20)/100 m = (1)/5 m , F = ? `
As work done in stopping the bullet = KE of bullet
`:. F (x) = (1)/(2) m upsilon^(2)`
`F = (1)/(2)(m upsilon^(2))/(x)= (1)/(2) xx (10^(-1)(20)^(2))/(1//5)= 100 N ` .