An open knife edge of mass 200 g is dropped from height 5 m on a cardboard. If the knife edge penetrates distance 2 m into the cardboard, the average resistance offered by the cardboard to the knife edge is (g=10m/s2)
1) 7 N
2) 25 N
3) 35 N
4) None
1) 7 N
2) 25 N
3) 35 N
4) None