Question

If contact force between 2kg & 4kg mass is f1 & between 4kg & 6 kg is f2. Find f1& f2 if 24N is applied on 2 kg mss& 12 N on 6kg in opposite direction

Answer 1

If contact force between 2kg & 4kg mass is f1 & between 4kg & 6 kg is f2. Find f1& f2 if 24N is applied on 2 kg mss& 12 N on 6kg in opposite direction

see free body diagram,

24N is applied on 2Kg and 12N is applied on 6kg in opposite direction, so net force applied on system = 24N - 12N = 12N (along 24N force , see diagram)

for block of mass 2Kg,

24N - f1 = 2a .....(1)

for block of mass 4kg ,

f1 - f2 = 4a .......(2)

for block of mass 6kg,

f2 - 12N = 6a ......(3)

solving equations (1), (2) and (3),

a = 1 m/s² and f1 = 24 - 2a = 24 - 2 = 22N

f2 = 6a + 12N = 18N

hence , magnitude of f1 = 22N

and magnitude of f2 = 18N