Question

Ten one-rupee coins are put on top of each other on a table. Each coin has a mass m. The reaction of the 6^th coin (counted from the bottom) on the 7^th coin is :

• A. 4mg
• B. 6mg
• C. 7mg
• D. 3mg

Answer 1

Answer: (A)

4mg

Answer 2

The sixth coin is under the weight of four coins above it. Hence

Reaction of the $6^{th}$coin on the $7^{th}$coin

= Force on the $6^{th}$ coin due to $7^{th}$ coin =4mg