question_answer 28)

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

Answer:

(i) Force on the 7th coin = Force due to 3 coins on its top . (ii) Force on the 7th coin by the 8th coin = Masses of 8th, 9th and 10th coins (iii) Reaction of the 6th coin on the 7th coin = Force on the 6th coin due to 7th coin = 4mg.