Twelve one-rupee coins are put on top of each other on a table, where mass of each coin is 20 g. The reaction of the 7 th coin (counted from bottom) on the 8 th coin is [take, g=10 m / s 2 ]

Question

Twelve one-rupee coins are put on top of each other on a table, where mass of each coin is 20 g. The reaction of the 7 th coin (counted from bottom) on the 8 th coin is [take, g=10 m / s 2 ] (A) 2 N (B) 1 N (C) 3 N (D) 4 N

Tardigrade Admin · Accepted Answer

According to question, 7th coin is under the weight of 5 coins above it. Hence, reaction of the 7th coin on the 8th coin = force on the 7th coin due to 8th coin = weight of 5 coins =5 m g=5 × 20 × 10-3 × 10= 1 N [∵ m=20 g =20 × 10-3 kg ]

Q. Twelve one-rupee coins are put on top of each other on a table, where mass of each coin is 20g. The reaction of the 7th coin (counted from bottom) on the 8th coin is [take, g=10m/s2 ]

2 N

1 N

3 N

4 N

According to question, 7th coin is under the weight of 5 coins above it. Hence, reaction of the 7th coin on the 8th coin = force on the 7th coin due to 8th coin = weight of 5 coins =5mg=5×20×10−3×10=1N [∵m=20g=20×10−3kg]

Q. Twelve one-rupee coins are put on top of each other on a table, where mass of each coin is $20 g$ . The reaction of the $7 t h$ coin (counted from bottom) on the $8 t h$ coin is [take, $g = 10 m / s^{2}$ ]