The maximum force than can be borne by the nut placed in a cracker (shown in the figure) is 200 N. The length of the cracker is 20 cm and the nut is placed at a distance of 15 cm from the free end of the cracker. If a boy can apply a maximum force of 25 N, find whether he can crack the nut. If not, find the length of the extension rod that should be attached to the cracker handle so that the boy can crack the nut.

Explanation

(i) Nut cracker is a second-order lever.
(ii) Find the load from the given information.
(iii) Find the lengths of the effort arm and the load arm from the given information.
(iv) Relate mechanical advantage, load and effort.
(v) Find the required effort and compare it with the force that can be exerted by the boy.
(vi) Consider the force that can be exerted by the boy as effort and find the length of the effort arm.
(vii) Compare the length of the effort arm obtained and its given length.
(viii) Boy cannot crack the nut Extension = 20 cm