Question

Find the valueo f friction forces between the blocks A

and B and between B and ground. [ g = 10 m/s 2 ]



A

B

5 kg

15 kg µ = 0.6

F = 80 N

µ = 0.1

1) 90 N , 5 N 2) 5 N , 90 N

3) 5 N , 75 N 4) 0N, 80 N​

Answer 1

In the given figure,

taking (A+B) as system

f s max between surface of B and earth is 120N

∴ The block will not move

∴ There is no acceleration of any block

∴ Net force on block is zero

frictional force on A=0N

and frictional force on B=80N

Answer 2

Answer:

In the given figure,

taking (A+B) as system

f

s

max between surface of B and earth is 120N

∴ The block will not move

∴ There is no acceleration of any block

∴ Net force on block is zero

frictional force on A=0N

and frictional force on B=80N