An open knife of mass m is dropped from a height h on a wooden floor. If the blade penetrates up to the depth d into the wood. The average resistance offered by the wood to the knife edge is .

Options

A. Mg
B. `Mg(1+h/S)`
C. `Mg(1-h/S)`
D. `Mg(1+h/S)^(2)`

Answer

B

Explanation

Work done = Decrease in P.E.
`FS=Mg(h+S)`
`F=Mg(1+h/S)`