An open knife of mass is dropped from a height onto a wooden floor

PHYSICS · Single correct · CBSE · Physics · Work, Energy and Power · Work, Energy and Power

Problem

An open knife of mass

m

is dropped from a height

h

onto a wooden floor. If the blade penetrates to a depth

d

into the wood, the average resistance offered by the wood to the knife edge is (1)

mg\left(1+\frac{h}{d}\right)

(2)

mg\left(1+\frac{h}{d}\right)^2

(3)

mg\left(1-\frac{h}{d}\right)

(4)

mg\left(1+\frac{d}{h}\right)