Ten one-rupee coins are put on top of each other on a table. Each coin has a mass m . Give the magnitude and direction of
(a) the force on the `7^(th)` coin (counted from the bottom due to all the coins on its top .
(b) the force on the `7^(th)` coin by the eigth coin.
(c ) the reaction of the `6^(th)` coin one th `7^(th)` coin .

Options

A. `0.3 N` downwards
B. `0.3 N` upwards
C. `0.7 N` downwards
D. `0.7 N` upwards

Answer

A

Explanation

Force on the seventh coin = weight of the three coins above it. `F=3mg`